Connector for positioning and stabilising structure

ABSTRACT

A patient interface comprising a plenum chamber pressurisable to a therapeutic pressure, a seal-forming structure constructed and arranged to maintain said therapeutic pressure in the plenum chamber, a positioning and stabilising structure to provide a force to hold a seal-forming structure in a therapeutically effective position on a patients head. The positioning and stabilising structure comprising at least one arm configured to be positioned adjacent to a cheek of the patient, and a strap removably received around the arm and configured to contact a posterior region of the patients head. The strap comprising a first coupling having a mechanical connector that is configured to engage the arm and limit movement of the arm into and out of the cavity, a second coupling spaced apart from an outer surface of the first coupling, and a sleeve being folded over the second coupling and positioned between the first and second couplings.

1 CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national phase of International ApplicationNo. PCT/AU2021/050049 filed Jan. 28, 2021 which designated the U.S. andclaims priority to Australian Provisional Application No. 2020900227filed Jan. 29, 2020, the entire contents of each of which are herebyincorporated by reference.

2 BACKGROUND OF THE TECHNOLOGY 2.1 Field of the Technology

The present technology relates to one or more of the screening,diagnosis, monitoring, treatment, prevention and amelioration ofrespiratory-related disorders. The present technology also relates tomedical devices or apparatus, and their use.

2.2 Description of the Related Art

2.2.1 Human Respiratory System and its Disorders

The respiratory system of the body facilitates gas exchange. The noseand mouth form the entrance to the airways of a patient.

The airways include a series of branching tubes, which become narrower,shorter and more numerous as they penetrate deeper into the lung. Theprime function of the lung is gas exchange, allowing oxygen to move fromthe inhaled air into the venous blood and carbon dioxide to move in theopposite direction. The trachea divides into right and left mainbronchi, which further divide eventually into terminal bronchioles. Thebronchi make up the conducting airways, and do not take part in gasexchange. Further divisions of the airways lead to the respiratorybronchioles, and eventually to the alveoli. The alveolated region of thelung is where the gas exchange takes place, and is referred to as therespiratory zone. See “Respiratory Physiology”, by John B. West,Lippincott Williams & Wilkins, 9th edition published 2012.

A range of respiratory disorders exist. Certain disorders may becharacterised by particular events, e.g. apneas, hypopneas, andhyperpneas.

Examples of respiratory disorders include Obstructive Sleep Apnea (OSA),Cheyne-Stokes Respiration (CSR), respiratory insufficiency, ObesityHyperventilation Syndrome (OHS), Chronic Obstructive Pulmonary Disease(COPD), Neuromuscular Disease (NMD) and Chest wall disorders.

Obstructive Sleep Apnea (OSA), a form of Sleep Disordered Breathing(SDB), is characterised by events including occlusion or obstruction ofthe upper air passage during sleep. It results from a combination of anabnormally small upper airway and the normal loss of muscle tone in theregion of the tongue, soft palate and posterior oropharyngeal wallduring sleep. The condition causes the affected patient to stopbreathing for periods typically of 30 to 120 seconds in duration,sometimes 200 to 300 times per night. It often causes excessive daytimesomnolence, and it may cause cardiovascular disease and brain damage.The syndrome is a common disorder, particularly in middle agedoverweight males, although a person affected may have no awareness ofthe problem. See U.S. Pat. No. 4,944,310 (Sullivan).

Respiratory failure is an umbrella term for respiratory disorders inwhich the lungs are unable to inspire sufficient oxygen or exhalesufficient CO₂ to meet the patient's needs. Respiratory failure mayencompass some or all of the following disorders.

A patient with respiratory insufficiency (a form of respiratory failure)may experience abnormal shortness of breath on exercise.

A range of therapies have been used to treat or ameliorate suchconditions. Furthermore, otherwise healthy individuals may takeadvantage of such therapies to prevent respiratory disorders fromarising. However, these have a number of shortcomings.

2.2.2 Therapies

Various respiratory therapies, such as Continuous Positive AirwayPressure (CPAP) therapy, Non-invasive ventilation (NIV), Invasiveventilation (IV), and High Flow Therapy (HFT) have been used to treatone or more of the above respiratory disorders.

2.2.2.1 Respiratory Pressure Therapies

Respiratory pressure therapy is the application of a supply of air to anentrance to the airways at a controlled target pressure that isnominally positive with respect to atmosphere throughout the patient'sbreathing cycle (in contrast to negative pressure therapies such as thetank ventilator or cuirass).

Continuous Positive Airway Pressure (CPAP) therapy has been used totreat Obstructive Sleep Apnea (OSA). The mechanism of action is thatcontinuous positive airway pressure acts as a pneumatic splint and mayprevent upper airway occlusion, such as by pushing the soft palate andtongue forward and away from the posterior oropharyngeal wall. Treatmentof OSA by CPAP therapy may be voluntary, and hence patients may electnot to comply with therapy if they find devices used to provide suchtherapy one or more of: uncomfortable, difficult to use, expensive andaesthetically unappealing.

2.2.2.2 Flow Therapies

Not all respiratory therapies aim to deliver a prescribed therapeuticpressure. Some respiratory therapies aim to deliver a prescribedrespiratory volume, by delivering an inspiratory flow rate profile overa targeted duration, possibly superimposed on a positive baselinepressure. In other cases, the interface to the patient's airways is‘open’ (unsealed) and the respiratory therapy may only supplement thepatient's own spontaneous breathing with a flow of conditioned orenriched gas. In one example, High Flow therapy (HFT) is the provisionof a continuous, heated, humidified flow of air to an entrance to theairway through an unsealed or open patient interface at a “treatmentflow rate” that is held approximately constant throughout therespiratory cycle. The treatment flow rate is nominally set to exceedthe patient's peak inspiratory flow rate. HFT has been used to treatOSA, CSR, respiratory failure, COPD, and other respiratory disorders.One mechanism of action is that the high flow rate of air at the airwayentrance improves ventilation efficiency by flushing, or washing out,expired CO₂ from the patient's anatomical deadspace. Hence, HFT is thussometimes referred to as a deadspace therapy (DST). Other benefits mayinclude the elevated warmth and humidification (possibly of benefit insecretion management) and the potential for modest elevation of airwaypressures. As an alternative to constant flow rate, the treatment flowrate may follow a profile that varies over the respiratory cycle.

Another form of flow therapy is long-term oxygen therapy (LTOT) orsupplemental oxygen therapy. Doctors may prescribe a continuous flow ofoxygen enriched air at a specified oxygen concentration (from 21%, theoxygen fraction in ambient air, to 100%) at a specified flow rate (e.g.,1 litre per minute (LPM), 2 LPM, 3 LPM, etc.) to be delivered to thepatient's airway.

2.2.2.3 Supplementary Oxygen

For certain patients, oxygen therapy may be combined with a respiratorypressure therapy or HFT by adding supplementary oxygen to thepressurised flow of air. When oxygen is added to respiratory pressuretherapy, this is referred to as RPT with supplementary oxygen. Whenoxygen is added to HFT, the resulting therapy is referred to as HFT withsupplementary oxygen.

2.2.3 Respiratory Therapy Systems

These respiratory therapies may be provided by a respiratory therapysystem or device. Such systems and devices may also be used to screen,diagnose, or monitor a condition without treating it.

A respiratory therapy system may comprise a Respiratory Pressure TherapyDevice (RPT device), an air circuit, a humidifier, a patient interface,an oxygen source, and data management.

2.2.3.1 Patient Interface

A patient interface may be used to interface respiratory equipment toits wearer, for example by providing a flow of air to an entrance to theairways. The flow of air may be provided via a mask to the nose and/ormouth, a tube to the mouth or a tracheostomy tube to the trachea of apatient. Depending upon the therapy to be applied, the patient interfacemay form a seal, e.g., with a region of the patient's face, tofacilitate the delivery of gas at a pressure at sufficient variance withambient pressure to effect therapy, e.g., at a positive pressure ofabout 10 cmH₂O relative to ambient pressure. For other forms of therapy,such as the delivery of oxygen, the patient interface may not include aseal sufficient to facilitate delivery to the airways of a supply of gasat a positive pressure of about 10 cmH₂O. For flow therapies such asnasal HFT, the patient interface is configured to insufflate the naresbut specifically to avoid a complete seal. One example of such a patientinterface is a nasal cannula.

Certain other mask systems may be functionally unsuitable for thepresent field. For example, purely ornamental masks may be unable tomaintain a suitable pressure. Mask systems used for underwater swimmingor diving may be configured to guard against ingress of water from anexternal higher pressure, but not to maintain air internally at a higherpressure than ambient.

Certain masks may be clinically unfavourable for the present technologye.g. if they block airflow via the nose and only allow it via the mouth.

Certain masks may be uncomfortable or impractical for the presenttechnology if they require a patient to insert a portion of a maskstructure in their mouth to create and maintain a seal via their lips.

Certain masks may be impractical for use while sleeping, e.g. forsleeping while lying on one's side in bed with a head on a pillow.

The design of a patient interface presents a number of challenges. Theface has a complex three-dimensional shape. The size and shape of nosesand heads varies considerably between individuals. Since the headincludes bone, cartilage and soft tissue, different regions of the facerespond differently to mechanical forces. The jaw or mandible may moverelative to other bones of the skull. The whole head may move during thecourse of a period of respiratory therapy.

As a consequence of these challenges, some masks suffer from being oneor more of obtrusive, aesthetically undesirable, costly, poorly fitting,difficult to use, and uncomfortable especially when worn for longperiods of time or when a patient is unfamiliar with a system. Wronglysized masks can give rise to reduced compliance, reduced comfort andpoorer patient outcomes. Masks designed solely for aviators, masksdesigned as part of personal protection equipment (e.g. filter masks),SCUBA masks, or for the administration of anaesthetics may be tolerablefor their original application, but nevertheless such masks may beundesirably uncomfortable to be worn for extended periods of time, e.g.,several hours. This discomfort may lead to a reduction in patientcompliance with therapy. This is even more so if the mask is to be wornduring sleep.

CPAP therapy is highly effective to treat certain respiratory disorders,provided patients comply with therapy. If a mask is uncomfortable, ordifficult to use a patient may not comply with therapy. Since it isoften recommended that a patient regularly wash their mask, if a mask isdifficult to clean (e.g., difficult to assemble or disassemble),patients may not clean their mask and this may impact on patientcompliance.

While a mask for other applications (e.g. aviators) may not be suitablefor use in treating sleep disordered breathing, a mask designed for usein treating sleep disordered breathing may be suitable for otherapplications.

For these reasons, patient interfaces for delivery of CPAP during sleepform a distinct field.

2.2.3.1.1 Seal-Forming Structure

Patient interfaces may include a seal-forming structure. Since it is indirect contact with the patient's face, the shape and configuration ofthe seal-forming structure can have a direct impact the effectivenessand comfort of the patient interface.

A patient interface may be partly characterised according to the designintent of where the seal-forming structure is to engage with the face inuse. In one form of patient interface, a seal-forming structure maycomprise a first sub-portion to form a seal around the left naris and asecond sub-portion to form a seal around the right naris. In one form ofpatient interface, a seal-forming structure may comprise a singleelement that surrounds both nares in use. Such single element may bedesigned to for example overlay an upper lip region and a nasal bridgeregion of a face. In one form of patient interface a seal-formingstructure may comprise an element that surrounds a mouth region in use,e.g. by forming a seal on a lower lip region of a face. In one form ofpatient interface, a seal-forming structure may comprise a singleelement that surrounds both nares and a mouth region in use. Thesedifferent types of patient interfaces may be known by a variety of namesby their manufacturer including nasal masks, full-face masks, nasalpillows, nasal puffs and oro-nasal masks.

A seal-forming structure that may be effective in one region of apatient's face may be inappropriate in another region, e.g. because ofthe different shape, structure, variability and sensitivity regions ofthe patient's face. For example, a seal on swimming goggles thatoverlays a patient's forehead may not be appropriate to use on apatient's nose.

Certain seal-forming structures may be designed for mass manufacturesuch that one design fit and be comfortable and effective for a widerange of different face shapes and sizes. To the extent to which thereis a mismatch between the shape of the patient's face, and theseal-forming structure of the mass-manufactured patient interface, oneor both must adapt in order for a seal to form.

One type of seal-forming structure extends around the periphery of thepatient interface, and is intended to seal against the patient's facewhen force is applied to the patient interface with the seal-formingstructure in confronting engagement with the patient's face. Theseal-forming structure may include an air or fluid filled cushion, or amoulded or formed surface of a resilient seal element made of anelastomer such as a rubber. With this type of seal-forming structure, ifthe fit is not adequate, there will be gaps between the seal-formingstructure and the face, and additional force will be required to forcethe patient interface against the face in order to achieve a seal.

Another type of seal-forming structure incorporates a flap seal of thinmaterial positioned about the periphery of the mask so as to provide aself-sealing action against the face of the patient when positivepressure is applied within the mask. Like the previous style of sealforming portion, if the match between the face and the mask is not good,additional force may be required to achieve a seal, or the mask mayleak. Furthermore, if the shape of the seal-forming structure does notmatch that of the patient, it may crease or buckle in use, giving riseto leaks.

Another type of seal-forming structure may comprise a friction-fitelement, e.g. for insertion into a naris, however some patients findthese uncomfortable.

Another form of seal-forming structure may use adhesive to achieve aseal. Some patients may find it inconvenient to constantly apply andremove an adhesive to their face.

A range of patient interface seal-forming structure technologies aredisclosed in the following patent applications, assigned to ResMedLimited: WO 1998/004,310; WO 2006/074,513; WO 2010/135,785.

One form of nasal pillow is found in the Adam Circuit manufactured byPuritan Bennett. Another nasal pillow, or nasal puff is the subject ofU.S. Pat. No. 4,782,832 (Trimble et al.), assigned to Puritan-BennettCorporation.

ResMed Limited has manufactured the following products that incorporatenasal pillows: SWIFT™ nasal pillows mask, SWIFT™ II nasal pillows mask,SWIFT™ LT nasal pillows mask, SWIFT™ FX nasal pillows mask and MIRAGELIBERTY™ full-face mask. The following patent applications, assigned toResMed Limited, describe examples of nasal pillows masks: InternationalPatent Application WO2004/073,778 (describing amongst other thingsaspects of the ResMed Limited SWIFT™ nasal pillows), US PatentApplication 2009/0044808 (describing amongst other things aspects of theResMed Limited SWIFT™ LT nasal pillows); International PatentApplications WO 2005/063,328 and WO 2006/130,903 (describing amongstother things aspects of the ResMed Limited MIRAGE LIBERTY™ full-facemask); International Patent Application WO 2009/052,560 (describingamongst other things aspects of the ResMed Limited SWIFT™ FX nasalpillows).

2.2.3.1.2 Positioning and Stabilising

A seal-forming structure of a patient interface used for positive airpressure therapy is subject to the corresponding force of the airpressure to disrupt a seal. Thus a variety of techniques have been usedto position the seal-forming structure, and to maintain it in sealingrelation with the appropriate portion of the face.

One technique is the use of adhesives. See for example US PatentApplication Publication No. US 2010/0000534. However, the use ofadhesives may be uncomfortable for some.

Another technique is the use of one or more straps and/or stabilisingharnesses. Many such harnesses suffer from being one or more ofill-fitting, bulky, uncomfortable and awkward to use.

2.2.3.2 Respiratory Pressure Therapy (RPT) Device

A respiratory pressure therapy (RPT) device may be used individually oras part of a system to deliver one or more of a number of therapiesdescribed above, such as by operating the device to generate a flow ofair for delivery to an interface to the airways. The flow of air may bepressure-controlled (for respiratory pressure therapies) orflow-controlled (for flow therapies such as HFT). Thus RPT devices mayalso act as flow therapy devices. Examples of RPT devices include a CPAPdevice and a ventilator.

Air pressure generators are known in a range of applications, e.g.industrial-scale ventilation systems. However, air pressure generatorsfor medical applications have particular requirements not fulfilled bymore generalised air pressure generators, such as the reliability, sizeand weight requirements of medical devices. In addition, even devicesdesigned for medical treatment may suffer from shortcomings, pertainingto one or more of: comfort, noise, ease of use, efficacy, size, weight,manufacturability, cost, and reliability.

An example of the special requirements of certain RPT devices isacoustic noise.

Table of noise output levels of prior RPT devices (one specimen only,measured using test method specified in ISO 3744 in CPAP mode at 10cmH₂O).

A-weighted sound Year RPT Device name pressure level dB(A) (approx.)C-Series Tango ™ 31.9 2007 C-Series Tango ™ with Humidifier 33.1 2007 S8Escape ™ II 30.5 2005 S8 Escape ™ II with H4i ™ Humidifier 31.1 2005 S9AutoSet ™ 26.5 2010 S9 AutoSet ™ with H5i Humidifier 28.6 2010

One known RPT device used for treating sleep disordered breathing is theS9 Sleep Therapy System, manufactured by ResMed Limited. Another exampleof an RPT device is a ventilator. Ventilators such as the ResMedStellar™ Series of Adult and Paediatric Ventilators may provide supportfor invasive and non-invasive non-dependent ventilation for a range ofpatients for treating a number of conditions such as but not limited toNMD, OHS and COPD.

The ResMed Elisée™ 150 ventilator and ResMed VS III™ ventilator mayprovide support for invasive and non-invasive dependent ventilationsuitable for adult or paediatric patients for treating a number ofconditions. These ventilators provide volumetric and barometricventilation modes with a single or double limb circuit. RPT devicestypically comprise a pressure generator, such as a motor-driven bloweror a compressed gas reservoir, and are configured to supply a flow ofair to the airway of a patient. In some cases, the flow of air may besupplied to the airway of the patient at positive pressure. The outletof the RPT device is connected via an air circuit to a patient interfacesuch as those described above.

The designer of a device may be presented with an infinite number ofchoices to make. Design criteria often conflict, meaning that certaindesign choices are far from routine or inevitable. Furthermore, thecomfort and efficacy of certain aspects may be highly sensitive tosmall, subtle changes in one or more parameters.

2.2.3.3 Air Circuit

An air circuit is a conduit or a tube constructed and arranged to allow,in use, a flow of air to travel between two components of a respiratorytherapy system such as the RPT device and the patient interface. In somecases, there may be separate limbs of the air circuit for inhalation andexhalation. In other cases, a single limb air circuit is used for bothinhalation and exhalation.

2.2.3.4 Humidifier

Delivery of a flow of air without humidification may cause drying ofairways. The use of a humidifier with an RPT device and the patientinterface produces humidified gas that minimizes drying of the nasalmucosa and increases patient airway comfort. In addition, in coolerclimates, warm air applied generally to the face area in and about thepatient interface is more comfortable than cold air.

A range of artificial humidification devices and systems are known,however they may not fulfil the specialised requirements of a medicalhumidifier.

Medical humidifiers are used to increase humidity and/or temperature ofthe flow of air in relation to ambient air when required, typicallywhere the patient may be asleep or resting (e.g. at a hospital). Amedical humidifier for bedside placement may be small. A medicalhumidifier may be configured to only humidify and/or heat the flow ofair delivered to the patient without humidifying and/or heating thepatient's surroundings. Room-based systems (e.g. a sauna, an airconditioner, or an evaporative cooler), for example, may also humidifyair that is breathed in by the patient, however those systems would alsohumidify and/or heat the entire room, which may cause discomfort to theoccupants. Furthermore, medical humidifiers may have more stringentsafety constraints than industrial humidifiers

While a number of medical humidifiers are known, they can suffer fromone or more shortcomings. Some medical humidifiers may provideinadequate humidification, some are difficult or inconvenient to use bypatients.

2.2.3.5 Data Management

There may be clinical reasons to obtain data to determine whether thepatient prescribed with respiratory therapy has been “compliant”, e.g.that the patient has used their RPT device according to one or more“compliance rules”. One example of a compliance rule for CPAP therapy isthat a patient, in order to be deemed compliant, is required to use theRPT device for at least four hours a night for at least 21 of 30consecutive days. In order to determine a patient's compliance, aprovider of the RPT device, such as a health care provider, may manuallyobtain data describing the patient's therapy using the RPT device,calculate the usage over a predetermined time period, and compare withthe compliance rule. Once the health care provider has determined thatthe patient has used their RPT device according to the compliance rule,the health care provider may notify a third party that the patient iscompliant.

There may be other aspects of a patient's therapy that would benefitfrom communication of therapy data to a third party or external system.

Existing processes to communicate and manage such data can be one ormore of costly, time-consuming, and error-prone.

2.2.3.6 Mandibular Repositioning

A mandibular repositioning device (MRD) or mandibular advancement device(MAD) is one of the treatment options for sleep apnea and snoring. It isan adjustable oral appliance available from a dentist or other supplierthat holds the lower jaw (mandible) in a forward position during sleep.The MRD is a removable device that a patient inserts into their mouthprior to going to sleep and removes following sleep. Thus, the MRD isnot designed to be worn all of the time. The MRD may be custom made orproduced in a standard form and includes a bite impression portiondesigned to allow fitting to a patient's teeth. This mechanicalprotrusion of the lower jaw expands the space behind the tongue, putstension on the pharyngeal walls to reduce collapse of the airway anddiminishes palate vibration.

In certain examples a mandibular advancement device may comprise anupper splint that is intended to engage with or fit over teeth on theupper jaw or maxilla and a lower splint that is intended to engage withor fit over teeth on the upper jaw or mandible. The upper and lowersplints are connected together laterally via a pair of connecting rods.The pair of connecting rods are fixed symmetrically on the upper splintand on the lower splint.

In such a design the length of the connecting rods is selected such thatwhen the MRD is placed in a patient's mouth the mandible is held in anadvanced position. The length of the connecting rods may be adjusted tochange the level of protrusion of the mandible. A dentist may determinea level of protrusion for the mandible that will determine the length ofthe connecting rods.

Some MRDs are structured to push the mandible forward relative to themaxilla while other MADs, such as the ResMed Narval CC™ MRD are designedto retain the mandible in a forward position. This device also reducesor minimises dental and temporo-mandibular joint (TMJ) side effects.Thus, it is configured to minimises or prevent any movement of one ormore of the teeth.

2.2.3.7 Vent Technologies

Some forms of treatment systems may include a vent to allow the washoutof exhaled carbon dioxide. The vent may allow a flow of gas from aninterior space of a patient interface, e.g., the plenum chamber, to anexterior of the patient interface, e.g., to ambient.

The vent may comprise an orifice and gas may flow through the orifice inuse of the mask. Many such vents are noisy. Others may become blocked inuse and thus provide insufficient washout. Some vents may be disruptiveof the sleep of a bed partner 1100 of the patient 1000, e.g. throughnoise or focussed airflow.

ResMed Limited has developed a number of improved mask venttechnologies. See International Patent Application Publication No. WO1998/034,665; International Patent Application Publication No. WO2000/078,381; U.S. Pat. No. 6,581,594; US Patent Application PublicationNo. US 2009/0050156; US Patent Application Publication No. 2009/0044808.

Table of noise of prior masks (ISO 17510-2:2007, 10 cmH₂O pressure at 1m)

A-weighted A-weighted sound power sound pressure level dB(A) dB(A) YearMask name Mask type (uncertainty) (uncertainty) (approx.) Glue-on (*)nasal 50.9 42.9 1981 ResCare nasal 31.5 23.5 1993 standard (*) ResMednasal 29.5 21.5 1998 Mirage ™ (*) ResMed nasal 36 (3) 28 (3) 2000UltraMirage ™ ResMed nasal 32 (3) 24 (3) 2002 Mirage Activa ™ ResMednasal 30 (3) 22 (3) 2008 Mirage Micro ™ ResMed nasal 29 (3) 22 (3) 2008Mirage ™ SoftGel ResMed nasal 26 (3) 18 (3) 2010 Mirage ™ FX ResMednasal pillows 37   29   2004 Mirage Swift ™ (*) ResMed nasal pillows 28(3) 20 (3) 2005 Mirage Swift ™ II ResMed nasal pillows 25 (3) 17 (3)2008 Mirage Swift ™ LT ResMed AirFit nasal pillows 21 (3) 13 (3) 2014P10

Sound pressure values of a variety of objects are listed below

A-weighted sound Object pressure dB(A) Notes Vacuum cleaner: Nilfisk 68ISO 3744 at Walter Broadly Litter Hog: 1 m distance B+ GradeConversational speech 60 1 m distance Average home 50 Quiet library 40Quiet bedroom at night 30 Background in TV studio 202.2.4 Screening, Diagnosis, and Monitoring Systems

Polysomnography (PSG) is a conventional system for diagnosis andmonitoring of cardio-pulmonary disorders, and typically involves expertclinical staff to apply the system. PSG typically involves the placementof 15 to 20 contact sensors on a patient in order to record variousbodily signals such as electroencephalography (EEG), electrocardiography(ECG), electrooculograpy (EOG), electromyography (EMG), etc. PSG forsleep disordered breathing has involved two nights of observation of apatient in a clinic, one night of pure diagnosis and a second night oftitration of treatment parameters by a clinician. PSG is thereforeexpensive and inconvenient. In particular it is unsuitable for homescreening/diagnosis/monitoring of sleep disordered breathing.

Screening and diagnosis generally describe the identification of acondition from its signs and symptoms. Screening typically gives atrue/false result indicating whether or not a patient's SDB is severeenough to warrant further investigation, while diagnosis may result inclinically actionable information. Screening and diagnosis tend to beone-off processes, whereas monitoring the progress of a condition cancontinue indefinitely. Some screening/diagnosis systems are suitableonly for screening/diagnosis, whereas some may also be used formonitoring.

Clinical experts may be able to screen, diagnose, or monitor patientsadequately based on visual observation of PSG signals. However, thereare circumstances where a clinical expert may not be available, or aclinical expert may not be affordable. Different clinical experts maydisagree on a s condition. In addition, a given clinical expert mayapply a different standard at different times.

3 BRIEF SUMMARY OF THE TECHNOLOGY

The present technology is directed towards providing medical devicesused in the screening, diagnosis, monitoring, amelioration, treatment,or prevention of respiratory disorders having one or more of improvedcomfort, cost, efficacy, ease of use and manufacturability.

A first aspect of the present technology relates to apparatus used inthe screening, diagnosis, monitoring, amelioration, treatment orprevention of a respiratory disorder.

Another aspect of the present technology relates to methods used in thescreening, diagnosis, monitoring, amelioration, treatment or preventionof a respiratory disorder.

An aspect of certain forms of the present technology is to providemethods and/or apparatus that improve the compliance of patients withrespiratory therapy.

One form of the present technology is directed to a patient interfacethat may comprise: a plenum chamber; a seal-forming structure; and apositioning and stabilising structure. The patient interface may furthercomprise a vent structure. The patient interface may further beconfigured to leave the patient's mouth uncovered, or if theseal-forming structure is configured to seal around the patient's noseand mouth, the patient interface may be further configured to allow thepatient to breathe from ambient in the absence of a flow of pressurisedair through the plenum chamber inlet port.

Another aspect of the present technology is directed to a face-mountedinterface that may comprise: a facial interface, and a positioning andstabilising structure. The facial interface may be configured to contacta user's (such as a patient's) face. The positioning and stabilisingstructure structured to hold the facial interface in an effectiveposition against the user's face.

In some aspects, the face-mounted interface is a patient interface usedin screening, diagnosis, monitoring, amelioration, treatment orprevention of a respiratory disorder. However, the face-mountedinterface may be any device worn on a user's face. The user may be apatient, an operator, an observer, or any other person.

Another aspect of one form of the present technology is directed to apositioning and stabilising structure configured to connect to a facialinterface (e.g., a plenum chamber of a patient interface) and to providea force to hold the facial interface in an effective position on auser's head.

Another aspect of one form the present technology is directed to apatient interface comprising: a plenum chamber pressurisable to atherapeutic pressure; a seal-forming structure constructed and arrangedto form a seal with a region of a patient's face surrounding an entranceto a patient's airways for sealed delivery of a flow of air at thetherapeutic pressure, the seal-forming structure constructed andarranged to maintain said therapeutic pressure in the plenum chamberthroughout the patient's respiratory cycle in use; and a positioning andstabilising structure to provide a force to hold a seal-formingstructure in a therapeutically effective position on a patient's head,the positioning and stabilising structure comprising: at least onerigidized arm configured, in use, to be positioned adjacent to a cheekof the patient, and a strap removably received around the rigidized armand configured to contact, in use, a posterior region of the patient'shead.

Another aspect of one form of the present technology is directed to apositioning and stabilising structure configured to support a facialinterface (e.g., a plenum chamber of a patient interface), thepositioning and stabilising structure comprising: at least one rigidizedarm configured, in use, to be positioned adjacent to a cheek of theuser, and a strap removably received around the rigidized arm andconfigured to contact, in use, a posterior region of the user's head.

Another aspect of one form of the present technology is the a patientinterface comprising: a plenum chamber pressurisable to a therapeuticpressure; a seal-forming structure constructed and arranged to form aseal with a region of a patient's face surrounding an entrance to apatient's airways for sealed delivery of a flow of air at thetherapeutic pressure, and the seal-forming structure constructed andarranged to maintain said therapeutic pressure in the plenum chamberthroughout the patient's respiratory cycle in use; and a positioning andstabilising structure to provide a force to hold a seal-formingstructure in a therapeutically effective position on a patient's head,the positioning and stabilising structure comprising: at least one arm,a strap removably received around the arm, the strap comprising a firstrigid coupling having a mechanical connection that engages the rigidizedarm and limits movement of the rigidized arm into and out of a cavity ofthe strap.

Another aspect of one form of the present technology is directed to apositioning and stabilising structure configured to support a facialinterface (e.g., a plenum chamber of a patient interface), thepositioning and stabilising structure comprising: at least one arm, astrap removably received around the arm, the strap comprising a firstrigid coupling having a mechanical connection that engages the rigidizedarm and limits movement of the rigidized arm into and out of a cavity ofthe strap.

Another aspect of one form of the present technology is the a patientinterface comprising: a plenum chamber pressurisable to a therapeuticpressure; a seal-forming structure constructed and arranged to form aseal with a region of a patient's face surrounding an entrance to apatient's airways for sealed delivery of a flow of air at thetherapeutic pressure, and the seal-forming structure constructed andarranged to maintain said therapeutic pressure in the plenum chamberthroughout the patient's respiratory cycle in use; and a positioning andstabilising structure to provide a force to hold a seal-formingstructure in a therapeutically effective position on a patient's head,the positioning and stabilising structure comprising: a strap configuredto contact, in use, a posterior region of the patient's head, the strapcomprising, a first rigid coupling, a second rigid coupling spaced apartfrom an outer surface of the first rigid coupling, and the sleeve beingfolded over the second rigid coupling and positioned between the firstrigid coupling and the second rigid coupling.

Another aspect of one form of the present technology is directed to apositioning and stabilising structure configured to support a facialinterface (e.g., a plenum chamber of a patient interface), thepositioning and stabilising structure comprising: a strap configured tocontact, in use, a posterior region of the user's head, the strapcomprising, a first rigid coupling, a second rigid coupling spaced apartfrom an outer surface of the first rigid coupling, and the sleeve beingfolded over the second rigid coupling and positioned between the firstrigid coupling and the second rigid coupling.

Another aspect of one form of the present technology is the a patientinterface comprising: a plenum chamber pressurisable to a therapeuticpressure; a seal-forming structure constructed and arranged to form aseal with a region of a patient's face surrounding an entrance to apatient's airways for sealed delivery of a flow of air at thetherapeutic pressure; and a positioning and stabilising structure toprovide a force to hold a seal-forming structure in a therapeuticallyeffective position on a patient's head, the positioning and stabilisingstructure comprising: a first rigid coupling, and a sleeve constructedfrom a flexible material, the sleeve being folded over the first rigidcoupling.

Another aspect of one form of the present technology is directed to apositioning and stabilising structure configured to support a facialinterface (e.g., a plenum chamber of a patient interface), thepositioning and stabilising structure comprising: a first rigidcoupling, and a sleeve constructed from a flexible material, the sleevebeing folded over the first rigid coupling.

Another aspect of one form of the present technology is the a patientinterface comprising: a plenum chamber pressurisable to a therapeuticpressure; a seal-forming structure constructed and arranged to form aseal with a region of a patient's face surrounding an entrance to apatient's airways for sealed delivery of a flow of air at thetherapeutic pressure, and the seal-forming structure constructed andarranged to maintain said therapeutic pressure in the plenum chamberthroughout the patient's respiratory cycle in use; and a positioning andstabilising structure to provide a force to hold a seal-formingstructure in a therapeutically effective position on a patient's head,the positioning and stabilising structure comprising: at least one arm,and a strap removably received around the rigidized arm, the strapcomprising, a first coupling having a mechanical connector that isconfigure to engage the arm, a second coupling spaced apart from anouter surface of the first coupling, and a sleeve constructed from aflexible material.

Another aspect of one form of the present technology is directed to apositioning and stabilising structure configured to support a facialinterface (e.g., a plenum chamber of a patient interface), thepositioning and stabilising structure comprising: at least one arm, anda strap removably received around the rigidized arm, the strapcomprising, a first coupling having a mechanical connector that isconfigure to engage the arm, a second coupling spaced apart from anouter surface of the first coupling, and a sleeve constructed from aflexible material.

Another aspect of one form of the present technology is a patientinterface comprising: a plenum chamber pressurisable to the therapeuticpressure of at least 6 cmH₂O above ambient air pressure, said plenumchamber including a plenum chamber inlet port sized and structured toreceive a flow of air at a therapeutic pressure for breathing by apatient; a seal-forming structure constructed and arranged to form aseal with a region of the patient's face surrounding an entrance to thepatient's airways, said seal-forming structure having a hole thereinsuch that the flow of air at said therapeutic pressure is delivered toat least an entrance to the patient's nares, the seal-forming structureconstructed and arranged to maintain said therapeutic pressure in theplenum chamber throughout the patient's respiratory cycle in use; and apositioning and stabilising structure to provide a force to hold aseal-forming structure in a therapeutically effective position on thepatient's head, the positioning and stabilising structure comprising: atleast one rigidized arm configured, in use, to be positioned adjacent toa cheek of the patient; and a strap removably received around therigidized arm and configured to contact, in use, a posterior region ofthe patient's head, the strap comprising, a first rigid coupling formingan opening to a cavity, the rigidized arm being positionable through theopening and into the cavity, the first rigid coupling having amechanical connector that is configured to engage the rigidized arm andlimit movement of the rigidized arm into and out of the cavity, a secondrigid coupling spaced apart from an outer surface of the first rigidcoupling, and a sleeve constructed from a flexible material, the sleevebeing folded over the second rigid coupling and positioned between thefirst rigid coupling and the second rigid coupling.

In certain forms, the sleeve includes an outer surface that comprisesthe outermost surface of the strap, and an inner surface that comprisesa boundary of the cavity.

In certain forms, the mechanical connector of the first rigid couplingincludes a projection, and the rigidized arm includes a recessconfigured to receive the projection.

In certain forms, the projection extends at an angle between 40° and 60°from an inner surface of the first rigid coupling.

In certain forms, the mechanical connector comprises a snap-fitconnection.

In certain forms, the flexible material is a textile.

In certain forms, the flexible material is elastic and/or elastomeric.

In certain forms, the first rigid coupling and the second rigid couplinghave a generally circular shape, the rigidized arm further including anextension having at least a portion of the generally circular shape.

In certain forms, the rigidized arm is configured to not extend in aposterior direction further than the patient's ear.

In certain forms, the strap includes a first piece and a second piececoupled together using a length adjuster, wherein the length adjuster isconfigured to change a usable length of the strap.

In certain forms, the strap is bifurcated.

In certain forms, the at least one rigidized arm comprises a firstrigidized arm configured, in use, to be positioned on a left side of thepatient's head, a second rigidized arm coupled to the positioning andstabilising structure and configured, in use, to be positioned adjacentto a right cheek of the patient, and the strap is removably receivedaround the second rigidized arm, the strap comprising: a third rigidcoupling defining a second opening to the cavity, the second rigidizedarm being positionable through the second opening and into the cavity,the third rigid coupling having a mechanical connector that engages thesecond rigidized arm and limits movement of the second rigidized arminto and out of the second opening of the cavity, a fourth rigidcoupling spaced apart from an outer surface of the first rigid coupling,and the sleeve being folded over the fourth rigid coupling andpositioned between the third rigid coupling and the fourth rigidcoupling.

In certain forms, the plenum chamber inlet port is a first plenumchamber inlet port, the plenum chamber further includes a second plenumchamber inlet port, the first plenum chamber inlet port configured toreceive the flow of air at the therapeutic pressure, and the secondplenum chamber inlet port configured to receive a plug configured toprevent the flow of air at the therapeutic pressure from escaping.

In certain forms, the rigidized arm includes the plug.

In certain forms, the plug is removable from the second opening in orderto permit pressurized air to flow through the second opening.

In certain forms, the rigidized arm is at least partially flexible inorder to adjust a contour to substantially correspond to the cheek ofthe patient.

In certain forms, the seal-forming structure defines nasal pillows or acradle.

In certain forms, the first rigid coupling, the second rigid coupling,and the sleeve are coupled together using an adhesive.

In certain forms, the cavity includes a width less than a width of therigidized arm, and wherein the sleeve is configured to stretch uponreceiving the rigidized arm.

Another aspect of one form of the present technology is a patientinterface that is moulded or otherwise constructed with a perimetershape which is complementary to that of an intended wearer.

An aspect of one form of the present technology is a method ofmanufacturing the patient interface.

In certain forms, the method comprises the steps of forming the strapby: providing the flexible material; inserting the second coupling intothe cavity of the flexible material; folding an end of the flexiblematerial into the cavity to enclose the second coupling; and insertingthe first coupling into the cavity.

In certain forms, the method comprises the steps of connecting thepositioning and stabilising structure to the seal-forming structure by:providing a plenum chamber with a connection opening; and inserting aplug of the rigidized arm into the connection opening.

In certain forms, the method comprises applying an adhesive around theconnection opening in order to secure the plug within the opening.

In certain forms, the method comprises removing the plug from theconnection opening.

Another aspect of one form of the present technology is directed to apatient interface that may comprise: a plenum chamber; a seal-formingstructure; and a positioning and stabilising structure. The seal-formingstructure may include an inlet port and the plenum chamber may includeat least one connection port.

In certain forms, the inlet port is configured to receive pressurizedair and the at least one connection port is configured to receive a plugto limit fluid flow through the connection port.

In certain forms, the inlet port is configured to receive a cover andthe at least one connection port is configured to receive pressurizedair.

In certain forms, the positioning and stabilising structure is connectedat the connection port. The positioning and stabilising structure may beeither conduit headgear that conveys fluid from a top of a patient'shead to the plenum chamber. Or, the positioning and stabilisingstructure may be a plug connected to a rigidized arm.

Another aspect of one form of the present technology is directed to apositioning and stabilising structure configured to support a facialinterface (e.g., a plenum chamber of a patient interface), thepositioning and stabilising structure comprising: at least one rigidizedarm configured, in use, to be positioned adjacent to a cheek of theuser; and a strap removably received around the rigidized arm andconfigured to contact, in use, a posterior region of the user's head,the strap comprising, a first rigid coupling forming an opening to acavity, the rigidized arm being positionable through the opening andinto the cavity, the first rigid coupling having a mechanical connectorthat is configured to engage the rigidized arm and limit movement of therigidized arm into and out of the cavity, a second rigid coupling spacedapart from an outer surface of the first rigid coupling, and a sleeveconstructed from a flexible material, the sleeve being folded over thesecond rigid coupling and positioned between the first rigid couplingand the second rigid coupling.

An aspect of one form of the present technology is a method ofmanufacturing the positioning and stabilising structure.

In certain forms, the method of manufacturing the positioning andstabilising structure comprises the steps of forming the strap by:providing the flexible material; inserting the second coupling into thecavity of the flexible material; folding an end of the flexible materialinto the cavity to enclose the second coupling; and inserting the firstcoupling into the cavity.

Another aspect of one form of the present technology is a patientinterface comprising: a plenum chamber pressurisable to a therapeuticpressure of at least 6 cmH2O above ambient air pressure, said plenumchamber including a plenum chamber inlet port sized and structured toreceive a flow of air at the therapeutic pressure for breathing by thepatient, and a connection inlet port sized and structured to receive aflow of air at the therapeutic pressure for breathing by a patient; aseal-forming structure constructed and arranged to form a seal with aregion of the patient's face surrounding an entrance to the patient'sairways, said seal-forming structure having a hole therein such that theflow of air at said therapeutic pressure is delivered to at least anentrance to the patient's nares, the seal-forming structure constructedand arranged to maintain said therapeutic pressure in the plenum chamberthroughout the patient's respiratory cycle in use; and wherein theconnection inlet port is configured to removably receive a positioningand stabilising structure to provide a force to hold a seal-formingstructure in a therapeutically effective position on the patient's head,the positioning and stabilising structure comprising at least one of: arigidized arm configured to limit fluid flow through the connectioninlet port, and the arm configured to be positioned along the patient'scheek while in use; and a conduit headgear configured to convey the flowof air through the connection inlet port to the patient.

In certain forms, the rigidized arm is coupled to the connection inletport, the rigidized arm comprises: a plug removably received within theconnection inlet port and configured to limit the flow of air throughthe connection inlet port; and a rigidized arm portion configured to bepositioned adjacent to a cheek of the patient.

In certain forms, the plenum chamber inlet port is configured to receivethe flow of air when in use.

In certain forms, the conduit headgear is coupled to the connectioninlet port, the conduit headgear comprising: an inlet configured toreceive the flow of air, the inlet disposed on a superior portion of thepatient's head in use; and a hollow tube configured to convey the flowof air to the plenum chamber.

In certain forms, a cover is removably received within the plenumchamber inlet port while the conduit headgear is coupled to theconnection inlet port, the cover limiting fluid flow through the plenumchamber inlet port.

In certain forms, the rigidized arm and the conduit headgear areinterchangeably connectable to the connection inlet port.

An aspect of one form of the present technology is a method of using thepatient interface.

In certain forms, the method comprises: providing the seal formingstructure; selecting the positioning and stabilising structure from oneof the rigidized arm and the conduit headgear; connecting thepositioning and stabilising structure to the connection inlet port;connecting one of an air circuit and a cover to the plenum chamber inletport; and providing a flow of air through one of the positioning andstabilising structure and the air circuit, and limiting the flow of airusing one of the cover and the positioning and stabilising structure.

Another aspect of one form of the present technology is directed to apositioning and stabilising structure configured to support a facialinterface (e.g., a plenum chamber of a patient interface), thepositioning and stabilising structure comprising at least one of: arigidized arm configured to limit fluid flow through the connectioninlet port, and the arm configured to be positioned along the user'scheek while in use; and a conduit headgear configured to convey the flowof air through the connection inlet port to the user.

An aspect of one form of the present technology is a method of using thepositioning and stabilising structure.

An aspect of certain forms of the present technology is a medical devicethat is easy to use, e.g. by a person who does not have medicaltraining, by a person who has limited dexterity, vision or by a personwith limited experience in using this type of medical device.

An aspect of one form of the present technology is a portable RPT devicethat may be carried by a person, e.g., around the home of the person.

An aspect of one form of the present technology is a patient interfacethat may be washed in a home of a patient, e.g., in soapy water, withoutrequiring specialised cleaning equipment. An aspect of one form of thepresent technology is a humidifier tank that may be washed in a home ofa patient, e.g., in soapy water, without requiring specialised cleaningequipment.

The methods, systems, devices and apparatus described may be implementedso as to improve the functionality of a processor, such as a processorof a specific purpose computer, respiratory monitor and/or a respiratorytherapy apparatus. Moreover, the described methods, systems, devices andapparatus can provide improvements in the technological field ofautomated management, monitoring and/or treatment of respiratoryconditions, including, for example, sleep disordered breathing.

Of course, portions of the aspects may form sub-aspects of the presenttechnology. Also, various ones of the sub-aspects and/or aspects may becombined in various manners and also constitute additional aspects orsub-aspects of the present technology.

Other features of the technology will be apparent from consideration ofthe information contained in the following detailed description,abstract, drawings and claims.

4 BRIEF DESCRIPTION OF THE DRAWINGS

The present technology is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings, in whichlike reference numerals refer to similar elements including:

4.1 Respiratory Therapy Systems

FIG. 1A shows a system including a patient 1000 wearing a patientinterface 3000, in the form of nasal pillows, receiving a supply of airat positive pressure from an RPT device 4000. Air from the RPT device4000 is humidified in a humidifier 5000, and passes along an air circuit4170 to the patient 1000. A bed partner 1100 is also shown. The patientis sleeping in a supine sleeping position.

FIG. 1B shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a nasal mask, receiving a supply of airat positive pressure from an RPT device 4000. Air from the RPT device ishumidified in a humidifier 5000, and passes along an air circuit 4170 tothe patient 1000.

FIG. 1C shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a full-face mask, receiving a supply ofair at positive pressure from an RPT device 4000. Air from the RPTdevice is humidified in a humidifier 5000, and passes along an aircircuit 4170 to the patient 1000. The patient is sleeping in a sidesleeping position.

4.2 Respiratory System and Facial Anatomy

FIG. 2A shows an overview of a human respiratory system including thenasal and oral cavities, the larynx, vocal folds, oesophagus, trachea,bronchus, lung, alveolar sacs, heart and diaphragm.

FIG. 2B shows a view of a human upper airway including the nasal cavity,nasal bone, lateral nasal cartilage, greater alar cartilage, nostril,lip superior, lip inferior, larynx, hard palate, soft palate,oropharynx, tongue, epiglottis, vocal folds, oesophagus and trachea.

FIG. 2C is a front view of a face with several features of surfaceanatomy identified including the lip superior, upper vermilion, lowervermilion, lip inferior, mouth width, endocanthion, a nasal ala,nasolabial sulcus and cheilion. Also indicated are the directionssuperior, inferior, radially inward and radially outward.

FIG. 2D is a side view of a head with several features of surfaceanatomy identified including glabella, sellion, pronasale, subnasale,lip superior, lip inferior, supramenton, nasal ridge, alar crest point,otobasion superior and otobasion inferior. Also indicated are thedirections superior & inferior, and anterior & posterior.

FIG. 2E is a further side view of a head. The approximate locations ofthe Frankfort horizontal and nasolabial angle are indicated. The coronalplane is also indicated.

FIG. 2F shows a base view of a nose with several features identifiedincluding naso-labial sulcus, lip inferior, upper Vermilion, naris,subnasale, columella, pronasale, the major axis of a naris and themidsagittal plane.

FIG. 2G shows a side view of the superficial features of a nose.

FIG. 2H shows subcutaneal structures of the nose, including lateralcartilage, septum cartilage, greater alar cartilage, lesser alarcartilage, sesamoid cartilage, nasal bone, epidermis, adipose tissue,frontal process of the maxilla and fibrofatty tissue.

FIG. 2I shows a medial dissection of a nose, approximately severalmillimeters from the midsagittal plane, amongst other things showing theseptum cartilage and medial crus of greater alar cartilage.

FIG. 2J shows a front view of the bones of a skull including thefrontal, nasal and zygomatic bones. Nasal concha are indicated, as arethe maxilla, and mandible.

FIG. 2K shows a lateral view of a skull with the outline of the surfaceof a head, as well as several muscles. The following bones are shown:frontal, sphenoid, nasal, zygomatic, maxilla, mandible, parietal,temporal and occipital. The mental protuberance is indicated. Thefollowing muscles are shown: digastricus, masseter, sternocleidomastoidand trapezius.

FIG. 2L shows an anterolateral view of a nose.

4.3 Patient Interface

FIG. 3A shows a patient interface in the form of a nasal mask inaccordance with one form of the present technology.

FIG. 3B shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a positive sign, and a relatively large magnitude whencompared to the magnitude of the curvature shown in FIG. 3C.

FIG. 3C shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a positive sign, and a relatively small magnitude whencompared to the magnitude of the curvature shown in FIG. 3B.

FIG. 3D shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a value of zero.

FIG. 3E shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a negative sign, and a relatively small magnitude whencompared to the magnitude of the curvature shown in FIG. 3F.

FIG. 3F shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a negative sign, and a relatively large magnitude whencompared to the magnitude of the curvature shown in FIG. 3E.

FIG. 3G shows a cushion for a mask that includes two pillows. Anexterior surface of the cushion is indicated. An edge of the surface isindicated. Dome and saddle regions are indicated.

FIG. 3H shows a cushion for a mask. An exterior surface of the cushionis indicated. An edge of the surface is indicated. A path on the surfacebetween points A and B is indicated. A straight line distance between Aand B is indicated. Two saddle regions and a dome region are indicated.

FIG. 3I shows the surface of a structure, with a one dimensional hole inthe surface. The illustrated plane curve forms the boundary of a onedimensional hole.

FIG. 3J shows a cross-section through the structure of FIG. 3I. Theillustrated surface bounds a two dimensional hole in the structure ofFIG. 3I.

FIG. 3K shows a perspective view of the structure of FIG. 3I, includingthe two dimensional hole and the one dimensional hole. Also shown is thesurface that bounds a two dimensional hole in the structure of FIG. 3I.

FIG. 3L shows a mask having an inflatable bladder as a cushion.

FIG. 3M shows a cross-section through the mask of FIG. 3L, and shows theinterior surface of the bladder. The interior surface bounds the twodimensional hole in the mask.

FIG. 3N shows a further cross-section through the mask of FIG. 3L. Theinterior surface is also indicated.

FIG. 3O illustrates a left-hand rule.

FIG. 3P illustrates a right-hand rule.

FIG. 3Q shows a left ear, including the left ear helix.

FIG. 3R shows a right ear, including the right ear helix.

FIG. 3S shows a right-hand helix.

FIG. 3T shows a view of a mask, including the sign of the torsion of thespace curve defined by the edge of the sealing membrane in differentregions of the mask.

FIG. 3U shows a view of a plenum chamber 3200 showing a sagittal planeand a mid-contact plane.

FIG. 3V shows a view of a posterior of the plenum chamber of FIG. 3U.The direction of the view is normal to the mid-contact plane. Thesagittal plane in FIG. 3V bisects the plenum chamber into left-hand andright-hand sides.

FIG. 3W shows a cross-section through the plenum chamber of FIG. 3V, thecross-section being taken at the sagittal plane shown in FIG. 3V. A‘mid-contact’ plane is shown. The mid-contact plane is perpendicular tothe sagittal plane. The orientation of the mid-contact plane correspondsto the orientation of a chord 3210 which lies on the sagittal plane andjust touches the cushion of the plenum chamber at two points on thesagittal plane: a superior point 3220 and an inferior point 3230.Depending on the geometry of the cushion in this region, the mid-contactplane may be a tangent at both the superior and inferior points.

FIG. 3X shows the plenum chamber 3200 of FIG. 3U in position for use ona face. The sagittal plane of the plenum chamber 3200 generallycoincides with the midsagittal plane of the face when the plenum chamberis in position for use. The mid-contact plane corresponds generally tothe ‘plane of the face’ when the plenum chamber is in position for use.In FIG. 3X the plenum chamber 3200 is that of a nasal mask, and thesuperior point 3220 sits approximately on the sellion, while theinferior point 3230 sits on the lip superior.

4.4 RPT Device

FIG. 4A shows an RPT device in accordance with one form of the presenttechnology.

FIG. 4B is a schematic diagram of the pneumatic path of an RPT device inaccordance with one form of the present technology. The directions ofupstream and downstream are indicated with reference to the blower andthe patient interface. The blower is defined to be upstream of thepatient interface and the patient interface is defined to be downstreamof the blower, regardless of the actual flow direction at any particularmoment. Items which are located within the pneumatic path between theblower and the patient interface are downstream of the blower andupstream of the patient interface.

4.5 Breathing Waveforms

FIG. 5 shows a model typical breath waveform of a person while sleeping.

4.6 Patient Interface of the Present Technology

FIG. 6A shows a perspective view of an air circuit disconnected from apatient interface.

FIG. 6B shows a perspective view of the air circuit of FIG. 6A coupledto the patient interface.

FIG. 6C shows a perspective view of the patient interface of FIG. 6Awith a back strap exploded in order to illustrate a pair of arms.

FIG. 6D shows a perspective view of the patient interface of FIG. 6A,with the back strap coupled to the pair of arms.

FIG. 6E shows a detail view of the patient interface of FIG. 6A,illustrating an arm of a positioning and stabilising structure, and asleeve decoupled from the arm.

FIG. 6F shows a perspective view of the patient interface of FIG. 6E,illustrating the arm in a second bent position.

FIG. 6G shows a perspective view of the patient interface of FIG. 6A,illustrating the sleeve starting to be slide along the arm.

FIG. 6H shows a perspective view of the patient interface of FIG. 6A,illustrating the sleeve fully slid along the arm.

FIG. 6I shows a perspective view of the patient interface of FIG. 6A,illustrating the sleeve being removed from the arm.

FIG. 6J shows a perspective view of a patient wearing the patientinterface of FIG. 6A, illustrating the patient donning the patientinterface by sliding the sleeve along the arms.

FIG. 6K shows a perspective view of a patient wearing the patientinterface of FIG. 6A, illustrating the patient adjusting a length of thesleeve after the sleeve is coupled to a seal-forming structure.

FIG. 6L shows a cross-sectional view of a sleeve of the patientinterface of FIG. 6A, the sleeve in a disassembled position and an outercoupling being inserted into the sleeve.

FIG. 6M is a cross-sectional view of the sleeve of FIG. 6L, andillustrating the outer coupling positioned within the sleeve anddisplaced from an end of the sleeve.

FIG. 6N is a cross-sectional view of the sleeve of FIG. 6M, andillustrating the end of the sleeve being folded into the sleeve and overthe outer coupling.

FIG. 6O is a cross-sectional view of the sleeve of FIG. 6M, andillustrating an inner coupling being inserted into the sleeve.

FIG. 6P is a cross-sectional view of the sleeve of FIG. 6M, andillustrating the inner coupling received within the sleeve.

FIG. 6Q is a detail view of the sleeve of FIG. 6P, illustrating theangle of a projection.

FIG. 6R is a perspective view of the patient interface of FIG. 6A,illustrating the air circuit and the arms being disconnected from theseal-forming structure.

FIG. 6S is a rear perspective view of the seal-forming structure of FIG.6R.

FIG. 6T is a perspective view of the seal-forming structure of FIG. 6R,illustrating a plug being inserted into an opening of the seal-formingstructure.

FIG. 6U is a perspective view of the seal-forming structure of FIG. 6T,illustrating the plug being inserted into the opening of theseal-forming structure.

FIG. 6V is a perspective view of conduit headgear being coupled to theseal-forming structure of FIG. 6T.

FIG. 6W is a perspective view of the conduit headgear coupled to theseal-forming structure of FIG. 6T.

5 DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

Before the present technology is described in further detail, it is tobe understood that the technology is not limited to the particularexamples described herein, which may vary. It is also to be understoodthat the terminology used in this disclosure is for the purpose ofdescribing only the particular examples discussed herein, and is notintended to be limiting.

The following description is provided in relation to various exampleswhich may share one or more common characteristics and/or features. Itis to be understood that one or more features of any one example may becombinable with one or more features of another example or otherexamples. In addition, any single feature or combination of features inany of the examples may constitute a further example.

5.1 Therapy

In one form, the present technology comprises a method for treating arespiratory disorder comprising applying positive pressure to theentrance of the airways of a patient 1000.

In certain examples of the present technology, a supply of air atpositive pressure is provided to the nasal passages of the patient viaone or both nares.

In certain examples of the present technology, mouth breathing islimited, restricted or prevented.

5.2 Respiratory Therapy Systems

In one form, the present technology comprises a respiratory therapysystem for treating a respiratory disorder. The respiratory therapysystem may comprise an RPT device 4000 for supplying a flow of air tothe patient 1000 via an air circuit 4170 and a patient interface 3000.

In one form, the present technology comprises a face-contacting systemfor interacting with a user's face. The system may comprise a facialinterface that engages or contacts the user's face. The facial interfacemay include a patient interface 3000, or any other system that interactswith a user's face.

5.3 Patient Interface

A face-contacting system may include a facial interface that isconfigured to be positioned against or near a user's face. The facialinterface is positioned and arranged to interact with an anatomicalfeature on the user's face. One example of the facial interface is anon-invasive patient interface 3000.

A non-invasive patient interface 3000 in accordance with one aspect ofthe present technology comprises the following functional aspects: aseal-forming structure 3100, a plenum chamber 3200, a positioning andstabilising structure 3300, a vent 3400, one form of connection port3600 for connection to air circuit 4170, and a forehead support 3700. Insome forms a functional aspect may be provided by one or more physicalcomponents. In some forms, one physical component may provide one ormore functional aspects. In use the seal-forming structure 3100 isarranged to surround an entrance to the airways of the patient so as tomaintain positive pressure at the entrance(s) to the airways of thepatient 1000. The sealed patient interface 3000 is therefore suitablefor delivery of positive pressure therapy.

If a patient interface is unable to comfortably deliver a minimum levelof positive pressure to the airways, the patient interface may beunsuitable for respiratory pressure therapy.

The patient interface 3000 in accordance with one form of the presenttechnology is constructed and arranged to be able to provide a supply ofair at a positive pressure of at least 6 cmH₂O with respect to ambient.

The patient interface 3000 in accordance with one form of the presenttechnology is constructed and arranged to be able to provide a supply ofair at a positive pressure of at least 10 cmH₂O with respect to ambient.

The patient interface 3000 in accordance with one form of the presenttechnology is constructed and arranged to be able to provide a supply ofair at a positive pressure of at least 20 cmH₂O with respect to ambient.

5.3.1 Seal-Forming Structure

In one form of the present technology, a seal-forming structure 3100provides a target seal-forming region, and may additionally provide acushioning function. The seal-forming structure 3100 may also bereferred to as a cushion. In other examples of a face-contacting system,the cushion may contact the user's face and may not seal against theuser's face. The target seal-forming region is a region on theseal-forming structure 3100 where sealing may occur. The region wheresealing actually occurs—the actual sealing surface—may change within agiven treatment session, from day to day, and from patient to patient,depending on a range of factors including for example, where the patientinterface was placed on the face, tension in the positioning andstabilising structure and the shape of a patient's face.

In one form the target seal-forming region is located on an outsidesurface of the seal-forming structure 3100.

In certain forms of the present technology, the seal-forming structure3100 is constructed from a biocompatible material, e.g. silicone rubber.

A seal-forming structure 3100 in accordance with the present technologymay be constructed from a soft, flexible, resilient material such assilicone.

In certain forms of the present technology, a system is providedcomprising more than one a seal-forming structure 3100, each beingconfigured to correspond to a different size and/or shape range. Forexample the system may comprise one form of a seal-forming structure3100 suitable for a large sized head, but not a small sized head andanother suitable for a small sized head, but not a large sized head.

5.3.1.1 Sealing Mechanisms

In one form, the seal-forming structure includes a sealing flangeutilizing a pressure assisted sealing mechanism. In use, the sealingflange can readily respond to a system positive pressure in the interiorof the plenum chamber 3200 acting on its underside to urge it into tightsealing engagement with the face. The pressure assisted mechanism mayact in conjunction with elastic tension in the positioning andstabilising structure.

In one form, the seal-forming structure 3100 comprises a sealing flangeand a support flange. The sealing flange comprises a relatively thinmember with a thickness of less than about 1 mm, for example about 0.25mm to about 0.45 mm, which extends around the perimeter of the plenumchamber 3200. Support flange may be relatively thicker than the sealingflange. The support flange is disposed between the sealing flange andthe marginal edge of the plenum chamber 3200, and extends at least partof the way around the perimeter. The support flange is or includes aspring-like element and functions to support the sealing flange frombuckling in use.

In one form, the seal-forming structure may comprise a compressionsealing portion or a gasket sealing portion. In use the compressionsealing portion, or the gasket sealing portion is constructed andarranged to be in compression, e.g. as a result of elastic tension inthe positioning and stabilising structure.

In one form, the seal-forming structure comprises a tension portion. Inuse, the tension portion is held in tension, e.g. by adjacent regions ofthe sealing flange.

In one form, the seal-forming structure comprises a region having atacky or adhesive surface.

In certain forms of the present technology, a seal-forming structure maycomprise one or more of a pressure-assisted sealing flange, acompression sealing portion, a gasket sealing portion, a tensionportion, and a portion having a tacky or adhesive surface.

5.3.1.2 Nose Bridge or Nose Ridge Region

In one form, the non-invasive patient interface 3000 comprises aseal-forming structure that forms a seal in use on a nose bridge regionor on a nose-ridge region of the patient's face.

In one form, the seal-forming structure includes a saddle-shaped regionconstructed to form a seal in use on a nose bridge region or on anose-ridge region of the patient's face.

5.3.1.3 Upper Lip Region

In one form, the non-invasive patient interface 3000 comprises aseal-forming structure that forms a seal in use on an upper lip region(that is, the lip superior) of the patient's face.

In one form, the seal-forming structure includes a saddle-shaped regionconstructed to form a seal in use on an upper lip region of thepatient's face.

5.3.1.4 Chin-Region

In one form the non-invasive patient interface 3000 comprises aseal-forming structure that forms a seal in use on a chin-region of thepatient's face.

In one form, the seal-forming structure includes a saddle-shaped regionconstructed to form a seal in use on a chin-region of the patient'sface.

5.3.1.5 Forehead Region

In one form, the seal-forming structure that forms a seal in use on aforehead region of the patient's face. In such a form, the plenumchamber may cover the eyes in use.

5.3.1.6 Nasal Pillows

In one form (see e.g., FIG. 3G), the seal-forming structure of thenon-invasive patient interface 3000 comprises a pair of nasal puffs, ornasal pillows, each nasal puff or nasal pillow being constructed andarranged to form a seal with a respective naris of the nose of apatient.

Nasal pillows in accordance with an aspect of the present technologyinclude: a frusto-cone, at least a portion of which forms a seal on anunderside of the patient's nose, a stalk, a flexible region on theunderside of the frusto-cone and connecting the frusto-cone to thestalk. In addition, the structure to which the nasal pillow of thepresent technology is connected includes a flexible region adjacent thebase of the stalk. The flexible regions can act in concert to facilitatea universal joint structure that is accommodating of relative movementboth displacement and angular of the frusto-cone and the structure towhich the nasal pillow is connected. For example, the frusto-cone may beaxially displaced towards the structure to which the stalk is connected.

5.3.1.7 Under the Nose Mask

As shown in FIGS. 6A-6C, the seal-forming structure 3100 of the patientinterface 3000 comprises an under the nose mask, which may be similar tothe nasal pillows because a seal is formed proximate the patient'snostrils and leaves the patient's mouth exposed to the ambient. Theseal-forming structure 3100 in the form of an under the nose mask sealsaround an outer surface of the patient's nose.

In the illustrated form, the seal-forming structure 3100 may seal aroundthe outside of the nose and may include a single opening for eachnostril. In other forms, the seal-forming structure 3100 may include asingle opening that receives both nostrils.

5.3.2 Plenum Chamber

The plenum chamber 3200 has a perimeter that is shaped to becomplementary to the surface contour of the face of an average person inthe region where a seal will form in use. In use, a marginal edge of theplenum chamber 3200 is positioned in close proximity to an adjacentsurface of the face. Actual contact with the face is provided by theseal-forming structure 3100. The seal-forming structure 3100 may extendin use about the entire perimeter of the plenum chamber 3200. In someforms, the plenum chamber 3200 and the seal-forming structure 3100 areformed from a single homogeneous piece of material.

In certain forms of the present technology, the plenum chamber 3200 doesnot cover the eyes of the patient in use. In other words, the eyes areoutside the pressurised volume defined by the plenum chamber. Such formstend to be less obtrusive and/or more comfortable for the wearer, whichcan improve compliance with therapy.

In certain forms of the present technology, the plenum chamber 3200 isconstructed from a transparent material, e.g. a transparentpolycarbonate. The use of a transparent material can reduce theobtrusiveness of the patient interface, and help improve compliance withtherapy. The use of a transparent material can aid a clinician toobserve how the patient interface is located and functioning.

In certain forms of the present technology, the plenum chamber 3200 isconstructed from a translucent material. The use of a translucentmaterial can reduce the obtrusiveness of the patient interface, and helpimprove compliance with therapy.

As shown in FIGS. 6A and 6B, the plenum chamber 3200 includes an openingor connection port 3600. While exposed, the connection port 3600provides fluid communication between the ambient and the nostrils, evenwhen the seal-forming structure 3100 is sealed to the patient's face. Inthe illustrated form, the connection port 3600 defines an ellipticalshape, and is disposed in a center of the plenum chamber 3200. In otherforms, the connection port 3600 may have a different size or may definea different shape.

The connection port 3600 defines an opening for receiving a flow ofpressurized fluid. Specifically, the air circuit 4170 is connectable tothe connection port 3600 in order to provide a fluid path from a RPTdevice 4000 to the patient's airways. In the illustrated form, aprojection 3212 is coupled to the plenum chamber 3200, and extends intothe connection port 3600 (see e.g., FIG. 6A). The projection 3212 mayconnect to the air circuit 4170 and retain the air circuit 4170 withrespect to the plenum chamber 3200. For example, the air circuit mayinclude a ring 4171 formed from a rigid or semi-rigid material (e.g.,plastic). When the air circuit 4170 is completely connected to theplenum chamber 3200 (see e.g., FIG. 6B), the projection 3212 engages thering 4171 in a snap-fit arrangement (e.g., engagement of the projection3212 creates a substantially airtight seal, which can be broken byproviding a pulling force).

As shown in FIG. 6B, once the air circuit 4170 is coupled to the plenumchamber 3200, substantially no air is able to escape through theinterface between the plenum chamber 3200 and the ring 4171. Air may besupplied directly into the plenum chamber 3200 from the air circuit4170, in order to allow the patient to inhale pressurized air throughtheir nose (or mouth if an alternate mask is used).

5.3.3 Positioning and Stabilising Structure

The positioning and stabilising structure 3300 may be generally referredto as a structure that maintains the position of the facial interface ina desired position on the user's face.

In some forms, a single positioning and stabilising structure 3300 maybe usable with multiple types of facial interfaces. Other forms ofpositioning and stabilising structures may be usable only with a singletype of facial interface.

The seal-forming structure 3100 of the patient interface 3000 of thepresent technology may be held in sealing position in use by thepositioning and stabilising structure 3300.

In one form the positioning and stabilising structure 3300 provides aretention force at least sufficient to overcome the effect of thepositive pressure in the plenum chamber 3200 to lift off the face.

In one form the positioning and stabilising structure 3300 provides aretention force to overcome the effect of the gravitational force on thepatient interface 3000.

In one form the positioning and stabilising structure 3300 provides aretention force as a safety margin to overcome the potential effect ofdisrupting forces on the patient interface 3000, such as from tube drag,or accidental interference with the patient interface.

In one form of the present technology, a positioning and stabilisingstructure 3300 is provided that is configured in a manner consistentwith being worn by a patient while sleeping. In one example thepositioning and stabilising structure 3300 has a low profile, orcross-sectional thickness, to reduce the perceived or actual bulk of theapparatus. In one example, the positioning and stabilising structure3300 comprises at least one strap having a rectangular cross-section. Inone example the positioning and stabilising structure 3300 comprises atleast one flat strap.

In one form of the present technology, a positioning and stabilisingstructure 3300 is provided that is configured so as not to be too largeand bulky to prevent the patient from lying in a supine sleepingposition with a back region of the patient's head on a pillow.

In one form of the present technology, a positioning and stabilisingstructure 3300 is provided that is configured so as not to be too largeand bulky to prevent the patient from lying in a side sleeping positionwith a side region of the patient's head on a pillow.

In one form of the present technology, a positioning and stabilisingstructure 3300 is provided with a decoupling portion located between ananterior portion of the positioning and stabilising structure 3300, anda posterior portion of the positioning and stabilising structure 3300.The decoupling portion does not resist compression and may be, e.g. aflexible or floppy strap. The decoupling portion is constructed andarranged so that when the patient lies with their head on a pillow, thepresence of the decoupling portion prevents a force on the posteriorportion from being transmitted along the positioning and stabilisingstructure 3300 and disrupting the seal.

In one form of the present technology, a positioning and stabilisingstructure 3300 comprises a strap constructed from a laminate of a fabricpatient-contacting layer, a foam inner layer and a fabric outer layer.In one form, the foam is porous to allow moisture, (e.g., sweat), topass through the strap. In one form, the fabric outer layer comprisesloop material to engage with a hook material portion.

In certain forms of the present technology, a positioning andstabilising structure 3300 comprises a strap that is extensible, e.g.resiliently extensible. For example the strap may be configured in useto be in tension, and to direct a force to draw a seal-forming structure3100 into sealing contact with a portion of a patient's face. In anexample the strap may be configured as a tie.

The strap of the positioning and stabilising structure 3300 may be atleast partially constructed from an adaptive material (e.g., a moistureactivated material, a heat activated material, an auxetic material,and/or a combination of different materials) as described inPCT/SG2020/050792, which is incorporated herein by reference in itsentirety. The strap may expand to provide additional comfort to patientsunder various usage conditions.

In one form of the present technology, the positioning and stabilisingstructure comprises a first tie, the first tie being constructed andarranged so that in use at least a portion of an inferior edge thereofpasses superior to an otobasion superior of the patient's head andoverlays a portion of a parietal bone without overlaying the occipitalbone.

In one form of the present technology suitable for a nasal-only mask orfor a full-face mask, the positioning and stabilising structure includesa second tie, the second tie being constructed and arranged so that inuse at least a portion of a superior edge thereof passes inferior to anotobasion inferior of the patient's head and overlays or lies inferiorto the occipital bone of the patient's head.

In one form of the present technology suitable for a nasal-only mask orfor a full-face mask, the positioning and stabilising structure includesa third tie that is constructed and arranged to interconnect the firsttie and the second tie to reduce a tendency of the first tie and thesecond tie to move apart from one another.

In certain forms of the present technology, a positioning andstabilising structure 3300 comprises a strap that is bendable and e.g.non-rigid. An advantage of this aspect is that the strap is morecomfortable for a patient to lie upon while the patient is sleeping.

In certain forms of the present technology, a positioning andstabilising structure 3300 comprises a strap constructed to bebreathable to allow moisture vapour to be transmitted through the strap,

In certain forms of the present technology, a system is providedcomprising more than one positioning and stabilising structure 3300,each being configured to provide a retaining force to correspond to adifferent size and/or shape range. For example, the system may compriseone form of a positioning and stabilising structure 3300 suitable for alarge sized head, but not a small sized head, and another suitable for asmall sized head, but not a large sized head.

As shown in FIGS. 6A-6Q, the positioning and stabilising structure 3300may include a headgear assembly 3302 that includes a sleeve 3304 and apair of arms 3306 (e.g., a left arm and a right arm). Each of the arms3306 may be a rigidized arm 3306. Together, the sleeve 3304 and the arms3306 are coupled to the seal-forming structure 3100 and the plenumchamber 3200 in order to retain them against the patient's face in atherapeutically effective position (e.g., where substantially nopressurized air leaks between the patient's face and the seal-formingstructure 3100).

In the illustrated form, the sleeve 3304 is constructed from a flexiblematerial. This permits the sleeve 3304 to bend and flex, and conform todifferent contours of a patient's head.

In certain forms, the sleeve 3304 may be constructed from an elasticmaterial or have elastic properties. In other words, the sleeve 3304 maybe capable of stretching when a tensile force is applied, and returningto its original position when the tensile force is released. The sleeve3304 may be constructed from a textile that includes one or moreelastomeric properties, or an elastomeric material may be included inthe sleeve 3304 with the textile. For example, the sleeve 3304 may be atleast partially constructed from elastane, a thermoplastic elastomer(TPE), silicone, or a similar material. The sleeve 3304 may be woven,knitted, braided, molded, extruded, or otherwise formed. The sleeve 3304may include a generally flat, rectangular shape, and may be formed witha cavity 3308 that extends through the sleeve 3304, and is capable ofreceiving another object.

The textile may provide comfort to the user while the sleeve 3304 restsagainst their face (e.g., it is non-abrasive). The elastomeric materialmay allow the sleeve 3304 to stretch in order to better fit around thepatient's head (e.g., not be too tight). A portion of the sleeve 3304may also be bifurcated so that a portion of the sleeve 3304 includes twoseparate sections. For example, the sleeve 3304 may include a first rearsection 3310 a and a second rear section 3310 b. When the sleeve 3304 isworn by the patient, the first and second rear sections 3310 a, 3310 bcontact a posterior portion of the patient's head. The first rearsection 3310 a may be partially spaced from the second rear section 3310b, and may help to distribute a force from the sleeve 3304 on thepatient's head.

In certain forms, the sleeve 3304 may be formed as multiple pieces(e.g., a first portion 3304 a and a second portion 3304 b), and coupledtogether by a fastener 3312 (e.g., a buckle). The fastener 3312 changesa usable length of the sleeve 3304 (e.g., a length of the sleeve 3304that is exposed to the patient's head) in order to adjust the fitrelative to the patient's head. The usable length of the sleeve 3304plus a length of the seal-forming structure 3100 is approximately equalto a circumference of the patient's head. The patient may increase ordecrease the usable length (e.g., by moving the portion(s) 3304 a, 3304b relative to one another through the fastener 3312) so that the sleeve3304 is snug, but not tight against their head. In other forms, thesleeve 3304 may be formed as a single body, and the patient may beunable to adjust the usable length of the sleeve 3304. Instead, thepatient may select between different sized sleeves 3304 (e.g., sleeves3304 with different pre-selected usable lengths).

The sleeve 3304 may be at least partially rigidized (e.g., usingrigidized thread, or other rigid or semi-rigid material). The rigid orsemi-rigid material in the sleeve 3304 may control where the sleeve 3304is able to stretch (e.g., disposed on at least one side of the elasticor elastomeric material to allow stretching in a single direction). Thismay prevent the sleeve 3304 from stretching too far and breaking (e.g.,because the elastic or elastomeric material fails). The rigid orsemi-rigid material may also control the flexion of the sleeve 3304, andassist in maintaining a shape of the sleeve 3304. For example, the rigidor semi-rigid material may assist in maintaining the generallyrectangular shape of the sleeve 3304. The rigid or semi-rigid materialmay also provide stiffness to the sleeve 3304, and provide resistance tobending.

In other forms, the sleeve 3304 may be at least partially rigidized witha stiffening portion that may be mouldable or capable of being formedinto a shape so as to provide a better fit with the patient's face forimproved comfort. For example, the material of the stiffening portionsmay include thermoplastic or thermosoftening plastic which haveactivation agent dependent material properties e.g. its materialproperties such as stiffness is altered when its temperature is within apredetermined range. In other forms, the stiffening portions have analtered stiffness upon application of a treatment. Stiffening portionsmay alter its material properties, for example stiffness, upon otheractivation agents (other than temperature). An activation agent mayinclude, but is not limited to, an electrical current, a chemical, apressure, and/or a force. An example of a stiffening portion isdescribed in PCT/SG2020/050792, which is incorporated herein byreference in its entirety.

As shown in FIG. 6C, each end of the sleeve 3304 includes an opening3315 to the cavity 3308. Where the sleeve 3304 includes two separateportions 3304 a, 3304 b, the sleeve 3304 also includes two distinctcavities 3308 with two distinct openings 3315 (e.g., the cavity 3308 inthe first portion 3304 a does not connect with the cavity 3308 in thesecond portion 3304 b). Conversely, the sleeve 3304 may include a singlecavity 3308 if it is formed as a single body.

The opening 3315 to the cavity 3308 includes a generally round (e.g.,circular, elliptical, etc.) shape, as opposed to the generallyrectangular shape of the remainder of the sleeve 3304. The opening 3315to the cavity 3308 may also be wider than the remainder of the cavity3308 (e.g., an inner diameter of the opening is wider than the remainderof the sleeve). This may assist the cavity 3308 in receiving objects,because the wide opening 3315 allows objects to be more easily inserted.In the illustrated example, the opening 3315 is rigidly maintained withthe round shape so that the cavity is always accessible (e.g., thesleeve 3304 does not collapse on itself, thereby closing off the cavity3308).

As shown in FIG. 6C, a rigidized arm 3306 extends from either side ofthe seal-forming structure 3100. In the illustrated example, bothrigidized arms 3306 are substantially identical to each other (e.g.,have the same length), and the following features will be described withrespect to a single rigidized arm 3306, although they are included onboth.

As shown in FIGS. 6E and 6F, the rigidized arm 3306 includes a plug 3316situated at one end. The plug 3316 is formed from a rigid or semi-rigidmaterial, and is positioned adjacent to the seal-forming structure 3100.In some forms, the plug 3316 and the seal-forming structure 3100 may beformed as a unitary piece. In other forms, the plug 3316 may be coupledto the seal-forming structure 3100 (e.g., using one or more of afastener, an adhesive, a magnet, a press-fit, a snap-fit, etc.).

In certain forms, the plenum chamber 3200 includes an orifice 3202 on alateral surface (see e.g., FIG. 6S). The orifice 3202 may extend towarda center of the plenum chamber 3200, so that the orifice 3202 mayprovide fluid communication into and/or out of the plenum chamber 3200.The plug 3316 is inserted into the orifice 3202, and limits the ingressand egress of fluid (e.g., pressurized gas) through the orifice 3202.The plug 3316 may be secured using a press-fit, such that the frictionalengagement between the orifice 3202 and the plug 3316 limits any fluidfrom entering or exiting the orifice 3202. An adhesive (e.g., glue) maybe used in addition to a press-fit in order retain the plug 3316 withinthe orifice 3202. The plug 3316 may be permanently secured in theorifice 3202 (e.g., during assembly of the patient interface 3000) sothat the fluid is limited from flowing through the orifice 3202 afterassembly is complete.

A clipping body 3320 is coupled to the plug 3316, and is positionedoutside of the orifice 3202 while the plug 3316 is received within theorifice 3202. The clipping body 3320 is formed from a rigid material(e.g., hard plastic), and is configured to retain its shape. In theillustrated example, the clipping body 3320 forms at least a partiallyround shape (e.g., circular, elliptical, etc.). The shape of theclipping body 3320 may form substantially the same shape as the openingto the cavity 3308. This may allow the clipping body 3320 to be receivedwithin the cavity 3308.

In one form, the clipping body 3320 includes a first clipping bodyportion 3320 a and a second clipping body portion 3320 b. The clippingbody portions 3320 a, 3320 b may mirror each other, and may each definea portion of the partially round shape. At least one discontinuity(e.g., a gap) exists between the clipping body portions 3320 a, 3320 b,so that the clipping bodies do not form the entire partially roundshape. In the illustrated example, a pair of discontinuities existbetween the clipping body portions 3320 a, 3320 b, so that eachrespective clipping body portion 3320 a, 3320 b is independent from theother. In other examples, the clipping body 3320 may include a greateror fewer number of clipping body portions, dependent on the number ofdiscontinuities.

In one form, the clipping body 3320 includes apertures 3324 positionedthrough a surface of the clipping body 3320. The apertures 3324 may berectangular in shape, or may have any other suitable shape (e.g., round,triangular, pentagonal, etc.). In the illustrated form, each clippingbody portion 3320 a, 3320 b includes an aperture 3324. The apertures3324 are positioned approximately 180° apart (e.g., a straight linepasses through a center of both apertures 3324; see FIGS. 6E and 6S). Inother words, the apertures 3324 of the clipping body 3320 are onopposite sides of the clipping body 3320.

In one form, the clipping body 3320 is rigidly coupled to the plug 3316,and is not rotatable relative to the plug 3316. The orientation of theapertures 3324 with respect to one another, and to the plug 3316,remains constant. The clipping body 3320 may be capable of flexing(i.e., bending) relative to the plug 3316. The clipping body 3320 may belimited in the amount it is capable of flexing so that it does not break(e.g., snap off).

Each rigidized arm 3306 may comprise an arm portion 3328. An arm portion3328 includes a fixed end 3329 coupled to the plug 3316, and a free end3330 distal to the plug 3316. The fixed end 3329 may be permanentlycoupled to the plug 3316, so that the arm portion 3328 and the plug 3316cannot be separated. The arm portion 3328 extends between the clippingbody portions 3320 a, 3320 b so that the clipping body portions 3320 a,3320 b curve around the arm portion 3328. The arm portion 3328 also hasa relatively flat and elongated configuration, so that the arm portion3328 is spaced apart from the clipping body portions 3320 a, 3320 b. Thearm portion 3328 also includes rounded edges (e.g., proximate to thefree end 3330), and includes substantially no sharp edges or corners.The arm portion 3328 also includes a substantially smooth surface.

As shown in FIGS. 6E and 6F, the arm portion 3328 may be constructedfrom a semi-rigid material, which may be capable of some movement. Inother words, a patient may be capable of bending the arm portion 3328into a preferred position, and the arm portion 3328 is capable ofmaintaining the position after the patient removes the bending force.Specifically, the patient may be able to impart a curvature onto the armportion 3328 (e.g., concave to the patient's head, convex to thepatient's head, or both). The patient may be able to repeatedly adjustthe arm portion 3328 until a position preferred by the patient isachieved.

As shown in FIG. 6E, the arm portion 3328 is substantially straight(e.g., parallel to the sagittal plane of a patient), and includes littleto no curvature relative to the patient. A patient may grasp and bendthe arm portion 3328. In the illustrated example, the patient grasps thearm portion 3328 proximate the free end 3330, although the patient maygrasp the arm portion 3328 anywhere. A larger length of the arm portion3328 may be curved (i.e., concave and/or convex) if a single bend ismade proximate the center of the arm portion 3328, and proximate eitherof the ends 3329, 3330. The patient may grasp the arm portion 3328 atmultiple positions and create multiple bends along the length of the armportion 3328. Each bend may have the same or different radius ofcurvature relative to any other bend along the length of the arm portion3328.

As shown in FIG. 6F, the free end 3330 of the arm portion 3328 is bentinto a concave orientation with respect to the seal-forming structure3100. In this example, the remained of the arm portion 3328 remainsrelatively straight (e.g., neither concave nor convex). The patient mayfurther bend the arm portion 3328 along the remaining length, or mayleave sections of the arm portion 3328 straight. Once the patientfinishes bending the arm portion 3328, the curvature of the arm portion3328 is maintained until the patient attempts to re-bend the arm portion3328. In other words, the rigid or semi-rigid material of the armportion 3328 maintains the applied curvature, and does not return thearm portion 3328 to a neutral (e.g., straight) position when the bendingforce is removed.

As shown in FIGS. 6F and 6G, once the curvature of the arm portion 3328is set (e.g., in a patient desired position), the sleeve 3304 may beslid along the length of the arm portion 3328 in order to at leastpartially cover the arm portion 3328. The flexible material of thesleeve 3304 allows the sleeve 3304 to conform to any curvature that thearm portion 3328 has. For example, the sleeve 3304 is bendable in alldirections so that the sleeve 3304 may substantially match the shape ofthe arm portion 3328. The rigid or semi-rigid structure of the armportion 3328 keeps the sleeve 3304 in that shape. In other examples, thearm portion 3328 may be bent after the sleeve 3304 has been at leastpartially slid along.

As shown in FIG. 6G, the arm portion 3328 may be inserted into thecavity 3308 of the sleeve 3304. Said another way, the sleeve 3304 may beslipped over the arm portion 3328 via the cavity 3308. The free end 3330of the arm portion 3328 is first inserted into the sleeve 3304 via thecavity 3308. The arm portion 3328 is pushed further inside of the sleeve3304 (i.e., further into the cavity 3308) until substantially all of thearm portion 3328 is within the sleeve 3304. The rounded edges and sidesof the arm portions 3328 helps to limit or prevent snagging or tearingof the sleeve 3304 as the arm portion 3328 is being inserted. Saidanother way, the arm portion 3328 does not include sharp edges thatcould dig into and potentially tear a hole in the sleeve 3304. Thesmooth surface of the arm portions 3328 also assists in limitingsnagging or tearing of the sleeve 3304 while the arm portion 3328 isbeing inserted (i.e., because rough surfaces are limited from catchingon the sleeve 3304).

In other forms, the rigidized arm 3306 may include a substantially smallor no arm portion 3328. The sleeve 3304 may still connect to theclipping body 3320 as described. In some forms, the sleeve 3304 mayinclude greater stiffness to compensate for the reduced length of thearm portion 3328.

As shown in FIG. 6G, the sleeve 3304 may be moved (or translated) in adirection towards the plug 3316. Consequently, the sleeve 3304 isslipped over the arm portion 3328 to a greater extent. As shown in FIG.6H, the arm portion 3328 is fully inserted into the cavity 3308 of thesleeve 3304. Said another way, the opening 3315 of the cavity 3308 ispositioned proximate to the fixed end 3329 of the arm portion 3328. Thecavity 3308 may extend beyond the length of the arm portion 3328 (e.g.,a length of the cavity 3308 may be longer than a length of the armportion 3328), but the arm portion cannot extend any further into thecavity 3308, because the plug 3316 limits further translation of thesleeve 3304. The plug 3316 is wider than the opening 3315, and preventsfurther ingress of the arm portion 3328 into the cavity 3308. The sleeve3304 receives the clipping body portions 3320 a, 3320 b within thecavity 3308, and engages the clipping body portions 3320 a, 3320 b inorder to mechanically couple the sleeve 3304 to the rigidized arm 3306.The engagement between the sleeve 3304 and the rigidized arm 3306facilitates easy removal of the sleeve 3304 from the arm portion 3328because the mechanical connection can be easy broken (see e.g., FIG.6I). The sleeve 3304 is removed in the reverse of how it was positionedon the arm portion 3328. As shown in FIG. 6I, the sleeve 3304 may bemoved in a direction away from the plug 3316. Consequently, the sleeve3304 is slipped over the arm portion 3328 to a lesser extent.

As shown in FIG. 6J, the first portion 3304 a and the second portion3304 b of the sleeve 3304 may be slipped over the arm portions 3328 atsubstantially the same time, while the plenum chamber 3200 andseal-forming structure 3100 are positioned against the patient'soro-nasal region (e.g., the patient's nose and/or mouth). Each portion3304 a, 3304 b may be slipped over the respective arm portions 3328 asdescribed above, so that openings 3315 of the common cavity 3308 (orindividual cavities 3308) are positioned proximate to the respectiveplugs 3316. As the portions 3304 a, 3304 b are slipped on, thepositioning and stabilising structure 3300 becomes tighter against thepatient's head. In other words, the portions 3304 a, 3304 b are pulledtoward an anterior of the patient's head so that the sleeve 3304 isagainst a posterior of a patient's head (e.g., the sleeve 3304 is taut).

As shown in FIG. 6K, after the sleeve portions 3304 a, 3304 b have beenconnected to the respective plug 3316, the patient may adjust the usablelength of the sleeve 3304. The patient may use the fastener 3312 inorder to increase or decrease the usable length of the sleeve 3304, sothat the sleeve 3304 is comfortable against the patient's head. Saidanother way, the patient can adjust the usable length so that theseal-forming structure 3100 is snug against the patient's face but isnot too tight (e.g., not digging into the patient's face, not creatingred marks on their skin, etc.). Before adjusting the length of thesleeve 3304, the patient may position the sleeve 3304 along theposterior of their head. For example, the patient may move the sleeve3304 in the superior or inferior direction in order to provide anappropriate force to the seal-forming structure 3100, and/or to maximizecomfort for the patient. If the sleeve 3304 is bifurcated, the patientmay also change the position of each bifurcated section relative to theother in order to adjust force and/or comfort. The patient may alsoadjust the usable length prior to donning the positioning andstabilising structure 3300 (e.g., because the usable length was toosmall to don).

The patient may hold the seal-forming structure 3100 and/or the plenumchamber 3200 in place adjacent their oro-nasal region while adjustingthe usable length of the sleeve 3304. This helps to ensure a proper sealbetween the seal-forming structure 3100 and the patient's skin (e.g., inthe proper location, substantially no leaks, etc.). By holding theseal-forming structure 3100 in a desired location, the sleeve 3304 canbe tightened to the appropriate usable length. For example, the usablelength will be different depending on where the patient positions thesleeve 3304. Positioning the sleeve 3304 more superior on the patient'shead equates to a longer usable length to achieve the same sealing force(e.g., because the position of the seal-forming structure 3100 is alwayspositioned proximate the patient's nose and/or mouth).

As shown in FIGS. 6L-6Q, the sleeve 3304 is assembled by positioning afirst (or inner) coupling 3334 and a second (or outer) coupling 3338within both ends of the cavity 3308 (or cavities 3308). The couplings3334, 3338 are positioned proximate an end of the sleeve 3304, and mayform the opening 3315 in the sleeve 3304. In other words, the outercoupling 3338 includes a generally circular shape. The inner coupling3334 may also include the same generally circular shape.

As shown in FIG. 6L, when the sleeve 3304 is initially assembled,neither coupling 3334, 3338 is present within the cavity 3308. Thesleeve 3304 is generally flat, and the opening 3315 and the cavity 3308are generally closed off. Said another way, sides of the sleeve 3304 areproximate to one another so that an internal volume within the cavity3308 is low. The sleeve 3304 may have a generally rectangular shape, butis flexible and may be capable of changing shapes (e.g., to a circularcross-section). The outer coupling 3338 is selected and moved to aposition proximate to the sleeve 3304. The outer coupling 3338 has agenerally circular cross-section with a hollow center. In theillustrated example, the outer coupling 3338 also has a larger diameterthan the sleeve 3304.

As shown in Fig. M, the outer coupling 3338 is positioned within thecavity 3308 of the sleeve 3304. The flexible material of the sleeve 3304is capable of expanding in order to receive the outer coupling 3338. Inother words, the outer coupling 3338 stretches the sleeve 3304 as it isinserted into the cavity 3308, so that the end on the sleeve 3304 iswider than a center of the sleeve 3304. The opening 3315 of the cavity3308 may have a different shape than the rest of the cavity 3308. Theouter coupling 3338 retains the sleeve 3304 in the wider, generallycircular position, while the rest of the sleeve 3304 (and therefore, therest of the cavity 3308) remains in the generally flat, rectangularorientation. The outer coupling 3338 may be made from a rigid orsemi-rigid material (e.g., a hard plastic) so that it retains its shapeunder pressure. Said another way, a biasing or elastic force thatattempts to return the sleeve 3304 to its original position is unable tochange the shape of the outer coupling 3338.

As shown in FIG. 6M, the outer coupling 3338 is slid into the cavity3308, and spaced apart from the initial opening 3315 of the sleeve 3304.In other words, an edge (e.g., a free end 3342) of the sleeve 3304 isnot aligned with an edge of the outer coupling 3338. A portion of thesleeve 3304 extends beyond the outer coupling 3338 on either side (e.g.,left and right as viewed in FIG. 6M). The outer coupling 3338 may befastened to the sleeve 3304 at an appropriate location within the cavity3308. For example, the outer coupling 3338 may be fixed by using anadhesive (e.g., glue), using a mechanical fastener, using a magneticfastener, sewing, or by any similar means. Once the outer coupling 3338is positioned at the desired location, the free end 3342 of the sleeve3304 is folded inwardly on itself. In other words, the free end 3342 ofthe sleeve 3304 is folded so that it is positioned within the cavity3308. The free end 3342 is folded so that it rests on the surface of theouter coupling 3338. The outer coupling 3338 is therefore at leastpartially sandwiched between folds of the sleeve 3304. The further awayfrom the free end 3342 that the outer coupling 3338 is disposed, thegreater the length of the sleeve 3304 that may be folded over the outercoupling 3338. This length may only partially cover the outer coupling3338, or it may completely cover the outer coupling 3338 so that it iscompletely enclosed by the sleeve 3304. Once the free end 3342 isfolded, the outer end of the outer coupling 3338 (e.g., the left end asviewed in FIG. 6N) is substantially aligned with the opening 3315 of thecavity 3308. Thus, the shape of the outer coupling 3338 forms the shapeof the opening 3315 to the cavity 3308 once the free end 3342 is foldedover.

Once the free end 3342 of the sleeve 3304 is folded over the outercoupling 3338, the free end 3342 may be secured to the outer coupling3338 and/or to the sleeve 3304. For example, the outer coupling 3338 maybe fixed by using an adhesive (e.g., glue), using a mechanical fastener,using a magnetic fastener, sewing, or by any similar means. The free end3342 is fixed so that it does not unfold and move away from the outercoupling 3338. In some forms, the same means is used to couple both theouter coupling 3338 within the cavity 3308, and the free end 3342 to theouter coupling 3338 and/or to the sleeve 3304 (e.g., only a single meansis used). In some forms, the outer coupling 3338 may not be directlycoupled to the sleeve 3304. Instead, the free end 3342 may be foldedcompletely over the outer coupling 3338, and coupled to the sleeve 3304,thereby forming a pocket around the outer coupling 3338. The outercoupling 3338 may be movable (e.g., if it was not secured to the sleeve3304 itself), but only within the confines of the pocket.

As shown in FIG. 6O, the inner coupling 3334 is selected and moved to aposition proximate to the sleeve 3304. The inner coupling 3334 has agenerally circular cross-section with a hollow center. The outerdiameter of the inner coupling 3334 is less than the inner diameter ofthe outer coupling 3338. The inner coupling 3334 is positioned at theopening 3315 of the cavity 3308 (i.e., the edge of the outer coupling3338), and is narrower than the opening 3315 so that it may slide intothe opening 3315.

The inner coupling 3334 includes at least one projection 3346 thatextends toward a center of the inner coupling 3334. In the illustratedexample, the inner coupling 3334 includes a pair of projections 3346.The projections 3346 may extend away from the surface of the innercoupling 3334 at an angle θ (see e.g., FIG. 6Q). The angle θ may be anangle measured from an axis 3348 that is parallel to a radial axis ofthe inner coupling 3334. In some forms, the angle θ is between 10° and90°. In some forms, the angle θ is between 20° and 80°. In some forms,the angle θ is between 30° and 70°. In some forms, the angle θ isbetween 35° and 65°. In some forms, the angle θ is between 40° and 60°.In some forms, the angle θ is approximately 55°. In some forms, bothprojections 3346 extend at the same angle (e.g., are mirrors of oneanother).

The projection 3346 may extend to a point or may be rounded. Theprojections 3346 are spaced apart from one another so that they are notin contact with the other projections 3346. The projections 3346 also donot extend out of the inner coupling 3334. Said another way, theprojections 3346 are maintained entirely within the volume of the innercoupling 3334.

As shown in FIG. 6P, the inner coupling 3334 is slid into the cavity3308. The inner coupling 3334 rests on the free end 3342 of the sleeve3304 within the cavity 3308. As seen in cross-section, the sleeve 3304includes different layers of materials within the cavity 3308. Forexample, starting from the outside, the sleeve 3304 forms the outermostsurface of the positioning and stabilising structure 3300, the outercoupling 3338 is positioned directly inside of the sleeve 3304, the freeend 3342 of the sleeve 3304 is folded over the outer coupling 3338, andthe inner coupling 3334 is positioned directly inside of the free end3342. Thus, there are four layers, where no adjacent (or adjoining)layers are the same (e.g., the positioning and stabilising structure3300 alternates between flexible and rigid/semi-rigid).

The inner coupling 3334 may be secured within the cavity once the innercoupling 3334 is positioned within in the desired location. For example,the inner coupling 3334 may be fixed by using an adhesive (e.g., glue),using a mechanical fastener, using a magnetic fastener, sewing, or byany similar means. This location may be substantially aligned with theouter coupling 3338. For example, the inner and outer couplings 3334,3338 may be concentric, and the edges of the inner and outer couplings3334, 3338 may be aligned. In other words, the inner and outer couplings3334, 3338 may both be positioned at the opening 3315. The space betweenthe projections 3346 leaves a space through the opening 3315 and intothe cavity 3308.

Returning to FIGS. 6G-6I, the arm portion 3328 is narrower than thewidth between the projections 3346. The projections 3346 do not createresistance as the sleeve 3304 slides along the arm portion 3328. Saidanother way, although the projections 3346 may touch the arm portion3328, the projections 3346 do not make sliding the sleeve 3304 along thearm portion 3328 more difficult. The wider opening created by the outercoupling 3338 provides a large target area for a patient to insert thearm portion 3328. The shape of the sleeve 3304 (e.g., generallyrectangular) does not generally change when the arm portion 3328 isinserted.

As shown in FIG. 6H, the opening 3315 of the sleeve 3304 is slid up tothe plug 3316. The clipping body portions 3320 a, 3320 b are receivedwithin the inner coupling 3334 when the arm portion 3328 is fullyreceived within the cavity 3308. The patient aligns the projections 3346of the inner coupling 3334 with the clipping body portions 3320 a, 3320b, so that the projections 3346 can be received within the clipping bodyportions 3320 a, 3320 b. The angle θ of the projection 3346 helps tomaintain the engagement between the respective projection 3346 and theclipping body 3320. Once the projections 3346 enter the respectiveclipping body portions 3320 a, 3320 b, the sleeve 3304 is retainedrelative to the plug 3316 (e.g., is not movable away from the plug3316).

With the sleeve 3304 secured in place, the positioning and stabilisingstructure 3300 is secured to the patient's head. As shown in FIGS. 6Jand 6K, the arm portions 3328 extend away from the oro-nasal region, andalong the patient's cheek, toward a posterior of the patient's head. Thearm portions 3328 also extend in a superior direction along thepatient's head (see e.g., FIG. 6K). In some forms, the arm portions 3328may not extend beyond the patient's respective ear. In other words, thefree end 3330 of the arm portion 3328 does not extend more posteriorthan the patient's ear. The arm portions 3328 extend so that they do notcontact the patient's ear. For example, the arm portions 3328 extendalong a line that projects superior to the patient's ear, so that thearm portion 3328 does not intersect the ear (e.g., and cause discomfortfor the patient). The sleeve 3304 extends from the oro-nasal region, tothe posterior of the patient's head, and back to the oro-nasal region.The sleeve 3304 follows the same line as the arm portion 3328, so thatthe sleeve 3304 also does not intersect the patient's ear.

In other forms (not shown), the free end 3330 of each arm portion 3328may extend to a point more anterior than the respective ear, and maycontact the patient's face at a location inferior to the otobasionsuperior and superior to the otobasion inferior. The sleeve 3304 maybifurcate in order to extend around and minimize contact with thepatient's ear.

Returning to FIG. 6I, the patient may disengage the projections 3346from the clipping body portions 3320 a, 3320 b in order to slide thesleeve 3304 off of the arm portion 3328. In some forms, the patient mayapply a suitable force directed away from the plug 3316 in order toremove the sleeve 3304. The applied force may cause the projections toexit the respective clipping body portions 3320 a, 3320 b, so that thesleeve 3304 is once again freely movable relative to the plug 3316. Inother forms, a force alone may be insufficient to remove the projections3346 from the clipping body portions 3320 a, 3320 b, without breakingthe projections 3346 (and thereby preventing future connections).Instead the patient may have to apply a compressive force to thecouplings 3334, 3338 prior to applying a force to the sleeve 3304 awayfrom the plug. Said another way, the patient squeezes the outer coupling3338 in order to compress the inner coupling 3334 and cause theprojections 3346 to leave the clipping body portions 3320 a, 3320 b. Atthis point, the inner coupling 3334 is no longer mechanically engaged tothe plug 3316, and can move relative to the plug 3316. The rigid orsemi-rigid material of the couplings 3334, 3338 may allow for smallamounts of flexion in order to allow the projections 3346 to move intoand out of the clipping body portions 3320 a, 3320 b.

As shown in FIG. 6R, the air circuit 4170 may be removed from the plenumchamber 3200 in order to expose a connection port 3600. Similarly, theplugs 3316 may be removed from the plenum chamber 3200. A plug 3316,clipping body 3320, and arm portion 3328 are formed as a single piece(e.g., they are connected to one another and not separable), so each areremoved from the plenum chamber 3200 together. In its place, the orifice3202 remains. Like the connection port 3600, the orifice 3202 providesfluid communication into the plenum chamber 3200. While the plugs 3316are positioned within the orifices 3202, ingress and egress of fluid(e.g., air) is substantially prevented, but air can freely enter andexit when the plugs 3316 are removed. The plugs 3316 may be connectedwith a press fit, a snap-fit, or a similar connection in order to allowrepeated insertion and removal of the plug 3316 (e.g., as shown in FIGS.6R and 6S), while limiting fluid flow through the respective orifice3202 when the respective plug 3316 is inserted. This may assist apatient in cleaning the interior of the plenum chamber 3200 (e.g., afteruse each night).

Alternatively, the plug 3316 may be integrally formed with the plenumchamber 3200 (or more broadly, a facial interface) in a one-piececonstruction. This may simplify the manufacturing (e.g., via molding) ofthe patient interface 3000 (or generally a face mounted interface). Theplug 3316 may still prevent or limit the ingress or egress of airflow,although an airflow path may not exist because of the integralformation.

As shown in FIGS. 6T-6W, a cover 3354 may be positioned over theconnection port 3600 in order to substantially prevent fluid fromentering and exiting the plenum chamber 3200. The cover 3354 connects tothe plenum chamber 3200 in the connection port 3600 with a friction fit,a press fit, a snap-fit, a magnetic engagement, or a similar connectionso that it can be removed, but also limits fluid flow through theconnection port 3600 when it is connected. A fluid conduit 3358 (e.g.,conduit headgear) can connect to the seal-forming structure 3100 at theorifice 3202. The fluid conduit 3358 is a hollow tube and includes aninlet 3362 in a center of the hollow tube. When worn by a patient, thefluid conduit 3358 may extend along a similar path as the arm portions3328 (e.g., along the cheek) toward the superior portion of thepatient's head. The air circuit 4170 can connect to the fluid conduit3358 at the inlet 3362 (i.e., on a superior region of the patient'shead), and provide pressurized air through the fluid conduit 3358 to theplenum chamber 3200. In other words, air flows from the inlet 3362,through the hollow tube of the fluid conduit 3358, and to the plenumchamber 3200. In this form (i.e., with the fluid conduit 3358connected), the fluid conduit 3358 may function as the positioning andstabilising structure 3300, and may provide some assistance in retainingthe seal-forming structure 3100 against the patient's face in atherapeutically effective position. Additionally, a rear strap 3366 maybe coupled to tabs 3370 of the fluid conduit 3358. The rear strap 3366may extend around a posterior of the patient's head (e.g., across thepatient's head proximate the occipital bone). The patient may then usethe patient interface 3000 modularly, and select how the pressurized airis delivered to their airways. A primary factor in determining this maybe comfort for the patient (e.g., where the air circuit 4170 extendsfrom the patient interface).

The fluid conduit 3358 may convey pressurized air toward theseal-forming structure 3100. The fluid conduit 3358 is made from and/orlined with an impermeable material (e.g., silicon, a thermoformed and/orlaminate structure, etc.). The fluid conduit 3358 couples to the plenumchamber 3200 with a seamless or substantially seamless transition (e.g.,within the orifice 3202) in order to prevent or substantially preventthe escape of pressurized air toward the ambient. In one example, thefluid conduit 3358 is dual lumen tubes.

5.3.4 Vent

In one form, the patient interface 3000 includes a vent 3400 constructedand arranged to allow for the washout of exhaled gases, e.g. carbondioxide.

In certain forms the vent 3400 is configured to allow a continuous ventflow from an interior of the plenum chamber 3200 to ambient whilst thepressure within the plenum chamber is positive with respect to ambient.The vent 3400 is configured such that the vent flow rate has a magnitudesufficient to reduce rebreathing of exhaled CO₂ by the patient whilemaintaining the therapeutic pressure in the plenum chamber in use.

One form of vent 3400 in accordance with the present technologycomprises a plurality of holes, for example, about 20 to about 80 holes,or about 40 to about 60 holes, or about 45 to about 55 holes.

The vent 3400 may be located in the plenum chamber 3200. Alternatively,the vent 3400 is located in a decoupling structure, e.g., a swivel.

5.3.5 Decoupling Structure(s)

In one form the patient interface 3000 includes at least one decouplingstructure, for example, a swivel or a ball and socket.

5.3.6 Connection Port

Connection port 3600 allows for connection to the air circuit 4170.

5.3.7 Forehead Support

In one form, the patient interface 3000 includes a forehead support3700.

5.3.8 Anti-Asphyxia Valve

In one form, the patient interface 3000 includes an anti-asphyxia valve.

5.3.9 Ports

In one form of the present technology, a patient interface 3000 includesone or more ports that allow access to the volume within the plenumchamber 3200. In one form this allows a clinician to supplysupplementary oxygen. In one form, this allows for the directmeasurement of a property of gases within the plenum chamber 3200, suchas the pressure.

5.4 RPT Device

An RPT device 4000 in accordance with one aspect of the presenttechnology comprises mechanical, pneumatic, and/or electrical componentsand is configured to execute one or more algorithms 4300, such as any ofthe methods, in whole or in part, described herein. The RPT device 4000may be configured to generate a flow of air for delivery to a patient'sairways, such as to treat one or more of the respiratory conditionsdescribed elsewhere in the present document.

In one form, the RPT device 4000 is constructed and arranged to becapable of delivering a flow of air in a range of −20 L/min to +150L/min while maintaining a positive pressure of at least 6 cmH₂O, or atleast 10cmH₂O, or at least 20 cmH₂O.

The RPT device may have an external housing 4010, formed in two parts,an upper portion 4012 and a lower portion 4014. Furthermore, theexternal housing 4010 may include one or more panel(s) 4015. The RPTdevice 4000 comprises a chassis 4016 that supports one or more internalcomponents of the RPT device 4000. The RPT device 4000 may include ahandle 4018.

The pneumatic path of the RPT device 4000 may comprise one or more airpath items, e.g., an inlet air filter 4112, an inlet muffler 4122, apressure generator 4140 capable of supplying air at positive pressure(e.g., a blower 4142), an outlet muffler 4124 and one or moretransducers 4270, such as pressure sensors and flow rate sensors.

One or more of the air path items may be located within a removableunitary structure which will be referred to as a pneumatic block 4020.The pneumatic block 4020 may be located within the external housing4010. In one form a pneumatic block 4020 is supported by, or formed aspart of the chassis 4016.

The RPT device 4000 may have an electrical power supply 4210, one ormore input devices 4220, a pressure generator 4140, and transducers4270. Electrical components 4200 may be mounted on a single PrintedCircuit Board Assembly (PCBA) 4202. In an alternative form, the RPTdevice 4000 may include more than one PCBA 4202.

5.4.1 RPT Device Mechanical & Pneumatic Components

An RPT device may comprise one or more of the following components in anintegral unit. In an alternative form, one or more of the followingcomponents may be located as respective separate units.

5.4.1.1 Air Filter(s)

An RPT device in accordance with one form of the present technology mayinclude an air filter 4110, or a plurality of air filters 4110.

In one form, an inlet air filter 4112 is located at the beginning of thepneumatic path upstream of a pressure generator 4140.

In one form, an outlet air filter 4114, for example an antibacterialfilter, is located between an outlet of the pneumatic block 4020 and apatient interface 3000.

5.4.1.2 Muffler(s)

An RPT device in accordance with one form of the present technology mayinclude a muffler 4120, or a plurality of mufflers 4120.

In one form of the present technology, an inlet muffler 4122 is locatedin the pneumatic path upstream of a pressure generator 4140.

In one form of the present technology, an outlet muffler 4124 is locatedin the pneumatic path between the pressure generator 4140 and a patientinterface 3000.

5.4.1.3 Pressure Generator

In one form of the present technology, a pressure generator 4140 forproducing a flow, or a supply, of air at positive pressure is acontrollable blower 4142. For example the blower 4142 may include abrushless DC motor 4144 with one or more impellers. The impellers may belocated in a volute. The blower may be capable of delivering a supply ofair, for example at a rate of up to about 120 litres/minute, at apositive pressure in a range from about 4 cmH₂O to about 20 cmH₂O, or inother forms up to about 30 cmH₂O when delivering respiratory pressuretherapy. The blower may be as described in any one of the followingpatents or patent applications the contents of which are incorporatedherein by reference in their entirety: U.S. Pat. Nos. 7,866,944;8,638,014; 8,636,479; and PCT Patent Application Publication No. WO2013/020167.

The pressure generator 4140 may be under the control of the therapydevice controller 4240.

In other forms, a pressure generator 4140 may be a piston-driven pump, apressure regulator connected to a high pressure source (e.g. compressedair reservoir), or a bellows.

5.4.1.4 Transducer(s)

Transducers may be internal of the RPT device, or external of the RPTdevice. External transducers may be located for example on or form partof the air circuit, e.g., the patient interface. External transducersmay be in the form of non-contact sensors such as a Doppler radarmovement sensor that transmit or transfer data to the RPT device.

In one form of the present technology, one or more transducers 4270 arelocated upstream and/or downstream of the pressure generator 4140. Theone or more transducers 4270 may be constructed and arranged to generatesignals representing properties of the flow of air such as a flow rate,a pressure or a temperature at that point in the pneumatic path.

In one form of the present technology, one or more transducers 4270 maybe located proximate to the patient interface 3000.

In one form, a signal from a transducer 4270 may be filtered, such as bylow-pass, high-pass or band-pass filtering.

5.4.1.5 Anti-Spill Back Valve

In one form of the present technology, an anti-spill back valve 4160 islocated between the humidifier 5000 and the pneumatic block 4020. Theanti-spill back valve is constructed and arranged to reduce the riskthat water will flow upstream from the humidifier 5000, for example tothe motor 4144.

5.4.2 RPT Device Electrical Components

5.4.2.1 Power Supply

A power supply 4210 may be located internal or external of the externalhousing 4010 of the RPT device 4000.

In one form of the present technology, power supply 4210 provideselectrical power to the RPT device 4000 only. In another form of thepresent technology, power supply 4210 provides electrical power to bothRPT device 4000 and humidifier 5000.

5.4.2.2 Input Devices

In one form of the present technology, an RPT device 4000 includes oneor more input devices 4220 in the form of buttons, switches or dials toallow a person to interact with the device. The buttons, switches ordials may be physical devices, or software devices accessible via atouch screen. The buttons, switches or dials may, in one form, bephysically connected to the external housing 4010, or may, in anotherform, be in wireless communication with a receiver that is in electricalconnection to a central controller.

In one form, the input device 4220 may be constructed and arranged toallow a person to select a value and/or a menu option.

5.5 Air Circuit

An air circuit 4170 in accordance with an aspect of the presenttechnology is a conduit or a tube constructed and arranged to allow, inuse, a flow of air to travel between two components such as RPT device4000 and the patient interface 3000.

In particular, the air circuit 4170 may be in fluid connection with theoutlet of the pneumatic block 4020 and the patient interface. The aircircuit may be referred to as an air delivery tube. In some cases theremay be separate limbs of the circuit for inhalation and exhalation. Inother cases a single limb is used.

In some forms, the air circuit 4170 may comprise one or more heatingelements configured to heat air in the air circuit, for example tomaintain or raise the temperature of the air. The heating element may bein a form of a heated wire circuit, and may comprise one or moretransducers, such as temperature sensors. In one form, the heated wirecircuit may be helically wound around the axis of the air circuit 4170.The heating element may be in communication with a controller such as acentral controller. One example of an air circuit 4170 comprising aheated wire circuit is described in U.S. Pat. No. 8,733,349, which isincorporated herewithin in its entirety by reference.

5.5.1 Supplementary Gas Delivery

In one form of the present technology, supplementary gas, e.g. oxygen,4180 is delivered to one or more points in the pneumatic path, such asupstream of the pneumatic block 4020, to the air circuit 4170, and/or tothe patient interface 3000.

5.6 Humidifier

In one form of the present technology there is provided a humidifier5000 (e.g. as shown in FIG. 4B) to change the absolute humidity of airor gas for delivery to a patient relative to ambient air. Typically, thehumidifier 5000 is used to increase the absolute humidity and increasethe temperature of the flow of air (relative to ambient air) beforedelivery to the patient's airways.

5.7 Breathing Waveforms

FIG. 5 shows a model typical breath waveform of a person while sleeping.The horizontal axis is time, and the vertical axis is respiratory flowrate. While the parameter values may vary, a typical breath may have thefollowing approximate values: tidal volume Vt 0.5 L, inhalation time Ti1.6 s, peak inspiratory flow rate Qpeak 0.4 L/s, exhalation time Te 2.4s, peak expiratory flow rate Qpeak −0.5 L/s. The total duration of thebreath, Ttot, is about 4 s. The person typically breathes at a rate ofabout 15 breaths per minute (BPM), with Ventilation Vent about 7.5L/min. A typical duty cycle, the ratio of Ti to Ttot, is about 40%.

5.8 Glossary

For the purposes of the present technology disclosure, in certain formsof the present technology, one or more of the following definitions mayapply. In other forms of the present technology, alternative definitionsmay apply.

5.8.1 General

Air: In certain forms of the present technology, air may be taken tomean atmospheric air, and in other forms of the present technology airmay be taken to mean some other combination of breathable gases, e.g.oxygen enriched air.

Ambient: In certain forms of the present technology, the term ambientwill be taken to mean (i) external of the treatment system or patient,and (ii) immediately surrounding the treatment system or patient.

For example, ambient humidity with respect to a humidifier may be thehumidity of air immediately surrounding the humidifier, e.g. thehumidity in the room where a patient is sleeping. Such ambient humiditymay be different to the humidity outside the room where a patient issleeping.

In another example, ambient pressure may be the pressure immediatelysurrounding or external to the body.

In certain forms, ambient (e.g., acoustic) noise may be considered to bethe background noise level in the room where a patient is located, otherthan for example, noise generated by an RPT device or emanating from amask or patient interface. Ambient noise may be generated by sourcesoutside the room.

Automatic Positive Airway Pressure (APAP) therapy: CPAP therapy in whichthe treatment pressure is automatically adjustable, e.g. from breath tobreath, between minimum and maximum limits, depending on the presence orabsence of indications of SDB events.

Continuous Positive Airway Pressure (CPAP) therapy: Respiratory pressuretherapy in which the treatment pressure is approximately constantthrough a respiratory cycle of a patient. In some forms, the pressure atthe entrance to the airways will be slightly higher during exhalation,and slightly lower during inhalation. In some forms, the pressure willvary between different respiratory cycles of the patient, for example,being increased in response to detection of indications of partial upperairway obstruction, and decreased in the absence of indications ofpartial upper airway obstruction.

Flow rate: The volume (or mass) of air delivered per unit time. Flowrate may refer to an instantaneous quantity. In some cases, a referenceto flow rate will be a reference to a scalar quantity, namely a quantityhaving magnitude only. In other cases, a reference to flow rate will bea reference to a vector quantity, namely a quantity having bothmagnitude and direction. Flow rate may be given the symbol Q. ‘Flowrate’ is sometimes shortened to simply ‘flow’ or ‘airflow’.

In the example of patient respiration, a flow rate may be nominallypositive for the inspiratory portion of a breathing cycle of a patient,and hence negative for the expiratory portion of the breathing cycle ofa patient. Device flow rate, Qd, is the flow rate of air leaving the RPTdevice. Total flow rate, Qt, is the flow rate of air and anysupplementary gas reaching the patient interface via the air circuit.Vent flow rate, Qv, is the flow rate of air leaving a vent to allowwashout of exhaled gases. Leak flow rate, Ql, is the flow rate of leakfrom a patient interface system or elsewhere. Respiratory flow rate, Qr,is the flow rate of air that is received into the patient's respiratorysystem.

Flow therapy: Respiratory therapy comprising the delivery of a flow ofair to an entrance to the airways at a controlled flow rate referred toas the treatment flow rate that is typically positive throughout thepatient's breathing cycle.

Humidifier: The word humidifier will be taken to mean a humidifyingapparatus constructed and arranged, or configured with a physicalstructure to be capable of providing a therapeutically beneficial amountof water (H₂O) vapour to a flow of air to ameliorate a medicalrespiratory condition of a patient.

Leak: The word leak will be taken to be an unintended flow of air. Inone example, leak may occur as the result of an incomplete seal betweena mask and a patient's face. In another example leak may occur in aswivel elbow to the ambient.

Noise, conducted (acoustic): Conducted noise in the present documentrefers to noise which is carried to the patient by the pneumatic path,such as the air circuit and the patient interface as well as the airtherein. In one form, conducted noise may be quantified by measuringsound pressure levels at the end of an air circuit.

Noise, radiated (acoustic): Radiated noise in the present documentrefers to noise which is carried to the patient by the ambient air. Inone form, radiated noise may be quantified by measuring soundpower/pressure levels of the object in question according to ISO 3744.

Noise, vent (acoustic): Vent noise in the present document refers tonoise which is generated by the flow of air through any vents such asvent holes of the patient interface.

Oxygen enriched air: Air with a concentration of oxygen greater thanthat of atmospheric air (21%), for example at least about 50% oxygen, atleast about 60% oxygen, at least about 70% oxygen, at least about 80%oxygen, at least about 90% oxygen, at least about 95% oxygen, at leastabout 98% oxygen, or at least about 99% oxygen. “Oxygen enriched air” issometimes shortened to “oxygen”.

Medical Oxygen: Medical oxygen is defined as oxygen enriched air with anoxygen concentration of 80% or greater.

Patient: A person, whether or not they are suffering from a respiratorycondition.

Pressure: Force per unit area. Pressure may be expressed in a range ofunits, including cmH₂O, g-f/cm² and hectopascal. 1 cmH₂O is equal to 1g-f/cm² and is approximately 0.98 hectopascal (1 hectopascal=100 Pa=100N/m²=1 millibar 0.001 atm). In this specification, unless otherwisestated, pressure is given in units of cmH₂O.

The pressure in the patient interface is given the symbol Pm, while thetreatment pressure, which represents a target value to be achieved bythe interface pressure Pm at the current instant of time, is given thesymbol Pt.

Respiratory Pressure Therapy: The application of a supply of air to anentrance to the airways at a treatment pressure that is typicallypositive with respect to atmosphere.

Ventilator: A mechanical device that provides pressure support to apatient to perform some or all of the work of breathing.

5.8.1.1 Materials

Silicone or Silicone Elastomer: A synthetic rubber. In thisspecification, a reference to silicone is a reference to liquid siliconerubber (LSR) or a compression moulded silicone rubber (CMSR). One formof commercially available LSR is SILASTIC (included in the range ofproducts sold under this trademark), manufactured by Dow Corning.Another manufacturer of LSR is Wacker. Unless otherwise specified to thecontrary, an exemplary form of LSR has a Shore A (or Type A) indentationhardness in the range of about 35 to about 45 as measured using ASTMD2240

Polycarbonate: a thermoplastic polymer of Bisphenol-A Carbonate.

5.8.1.2 Mechanical Properties

Resilience: Ability of a material to absorb energy when deformedelastically and to release the energy upon unloading.

Resilient: Will release substantially all of the energy when unloaded.Includes e.g. certain silicones, and thermoplastic elastomers.

Hardness: The ability of a material per se to resist deformation (e.g.described by a Young's Modulus, or an indentation hardness scalemeasured on a standardised sample size).

-   -   ‘Soft’ materials may include silicone or thermo-plastic        elastomer (TPE), and may, e.g. readily deform under finger        pressure.    -   ‘Hard’ materials may include polycarbonate, polypropylene, steel        or aluminium, and may not e.g. readily deform under finger        pressure.

Stiffness (or rigidity) of a structure or component: The ability of thestructure or component to resist deformation in response to an appliedload. The load may be a force or a moment, e.g. compression, tension,bending or torsion. The structure or component may offer differentresistances in different directions. The inverse of stiffness isflexibility.

Floppy structure or component. A structure or component that will changeshape, e.g. bend, when caused to support its own weight, within arelatively short period of time such as 1 second.

Rigid structure or component: A structure or component that will notsubstantially change shape when subject to the loads typicallyencountered in use. An example of such a use may be setting up andmaintaining a patient interface in sealing relationship with an entranceto a patient's airways, e.g. at a load of approximately 20 to 30 cmH₂Opressure.

As an example, an I-beam may comprise a different bending stiffness(resistance to a bending load) in a first direction in comparison to asecond, orthogonal direction. In another example, a structure orcomponent may be floppy in a first direction and rigid in a seconddirection.

5.8.2 Respiratory Cycle

Apnea: According to some definitions, an apnea is said to have occurredwhen flow falls below a predetermined threshold for a duration, e.g. 10seconds. An obstructive apnea will be said to have occurred when,despite patient effort, some obstruction of the airway does not allowair to flow. A central apnea will be said to have occurred when an apneais detected that is due to a reduction in breathing effort, or theabsence of breathing effort, despite the airway being patent. A mixedapnea occurs when a reduction or absence of breathing effort coincideswith an obstructed airway.

Breathing rate: The rate of spontaneous respiration of a patient,usually measured in breaths per minute.

Duty cycle: The ratio of inhalation time, Ti to total breath time, Ttot.

Effort (breathing): The work done by a spontaneously breathing personattempting to breathe.

Expiratory portion of a breathing cycle: The period from the start ofexpiratory flow to the start of inspiratory flow.

Flow limitation: Flow limitation will be taken to be the state ofaffairs in a patient's respiration where an increase in effort by thepatient does not give rise to a corresponding increase in flow. Whereflow limitation occurs during an inspiratory portion of the breathingcycle it may be described as inspiratory flow limitation. Where flowlimitation occurs during an expiratory portion of the breathing cycle itmay be described as expiratory flow limitation.

Types of flow limited inspiratory waveforms:

-   -   (i) Flattened: Having a rise followed by a relatively flat        portion, followed by a fall.    -   (ii) M-shaped: Having two local peaks, one at the leading edge,        and one at the trailing edge, and a relatively flat portion        between the two peaks.    -   (iii) Chair-shaped: Having a single local peak, the peak being        at the leading edge, followed by a relatively flat portion.    -   (iv) Reverse-chair shaped: Having a relatively flat portion        followed by single local peak, the peak being at the trailing        edge.

Hypopnea: According to some definitions, a hypopnea is taken to be areduction in flow, but not a cessation of flow. In one form, a hypopneamay be said to have occurred when there is a reduction in flow below athreshold rate for a duration. A central hypopnea will be said to haveoccurred when a hypopnea is detected that is due to a reduction inbreathing effort. In one form in adults, either of the following may beregarded as being hypopneas:

-   -   (i) a 30% reduction in patient breathing for at least 10 seconds        plus an associated 4% desaturation; or    -   (ii) a reduction in patient breathing (but less than 50%) for at        least 10 seconds, with an associated desaturation of at least 3%        or an arousal.

Hyperpnea: An increase in flow to a level higher than normal.

Inspiratory portion of a breathing cycle: The period from the start ofinspiratory flow to the start of expiratory flow will be taken to be theinspiratory portion of a breathing cycle.

Patency (airway): The degree of the airway being open, or the extent towhich the airway is open. A patent airway is open. Airway patency may bequantified, for example with a value of one (1) being patent, and avalue of zero (0), being closed (obstructed).

Positive End-Expiratory Pressure (PEEP): The pressure above atmospherein the lungs that exists at the end of expiration.

Peak flow rate (Qpeak): The maximum value of flow rate during theinspiratory portion of the respiratory flow waveform.

Respiratory flow rate, patient airflow rate, respiratory airflow rate(Qr): These terms may be understood to refer to the RPT device'sestimate of respiratory flow rate, as opposed to “true respiratory flowrate” or “true respiratory flow rate”, which is the actual respiratoryflow rate experienced by the patient, usually expressed in litres perminute.

Tidal volume (Vt): The volume of air inhaled or exhaled during normalbreathing, when extra effort is not applied. In principle theinspiratory volume Vi (the volume of air inhaled) is equal to theexpiratory volume Ve (the volume of air exhaled), and therefore a singletidal volume Vt may be defined as equal to either quantity. In practicethe tidal volume Vt is estimated as some combination, e.g. the mean, ofthe inspiratory volume Vi and the expiratory volume Ve.

(inhalation) Time (Ti): The duration of the inspiratory portion of therespiratory flow rate waveform.

(exhalation) Time (Te): The duration of the expiratory portion of therespiratory flow rate waveform.

(total) Time (Ttot): The total duration between the start of oneinspiratory portion of a respiratory flow rate waveform and the start ofthe following inspiratory portion of the respiratory flow rate waveform.

Typical recent ventilation: The value of ventilation around which recentvalues of ventilation Vent over some predetermined timescale tend tocluster, that is, a measure of the central tendency of the recent valuesof ventilation.

Upper airway obstruction (UAO): includes both partial and total upperairway obstruction. This may be associated with a state of flowlimitation, in which the flow rate increases only slightly or may evendecrease as the pressure difference across the upper airway increases(Starling resistor behaviour).

Ventilation (Vent): A measure of a rate of gas being exchanged by thepatient's respiratory system. Measures of ventilation may include one orboth of inspiratory and expiratory flow, per unit time. When expressedas a volume per minute, this quantity is often referred to as “minuteventilation”. Minute ventilation is sometimes given simply as a volume,understood to be the volume per minute.

5.8.3 Anatomy

5.8.3.1 Anatomy of the Face

Ala: the external outer wall or “wing” of each nostril (plural: alar)

Alare: The most lateral point on the nasal ala.

Alar curvature (or alar crest) point: The most posterior point in thecurved base line of each ala, found in the crease formed by the union ofthe ala with the cheek.

Auricle: The whole external visible part of the ear.

(nose) Bony framework: The bony framework of the nose comprises thenasal bones, the frontal process of the maxillae and the nasal part ofthe frontal bone.

(nose) Cartilaginous framework: The cartilaginous framework of the nosecomprises the septal, lateral, major and minor cartilages.

Columella: the strip of skin that separates the nares and which runsfrom the pronasale to the upper lip.

Columella angle: The angle between the line drawn through the midpointof the nostril aperture and a line drawn perpendicular to the Frankforthorizontal while intersecting subnasale.

Frankfort horizontal plane: A line extending from the most inferiorpoint of the orbital margin to the left tragion. The tragion is thedeepest point in the notch superior to the tragus of the auricle.

Glabella: Located on the soft tissue, the most prominent point in themidsagittal plane of the forehead.

Lateral nasal cartilage: A generally triangular plate of cartilage. Itssuperior margin is attached to the nasal bone and frontal process of themaxilla, and its inferior margin is connected to the greater alarcartilage.

Greater alar cartilage: A plate of cartilage lying below the lateralnasal cartilage. It is curved around the anterior part of the naris. Itsposterior end is connected to the frontal process of the maxilla by atough fibrous membrane containing three or four minor cartilages of theala.

Nares (Nostrils): Approximately ellipsoidal apertures forming theentrance to the nasal cavity. The singular form of nares is naris(nostril). The nares are separated by the nasal septum.

Naso-labial sulcus or Naso-labial fold: The skin fold or groove thatruns from each side of the nose to the corners of the mouth, separatingthe cheeks from the upper lip.

Naso-labial angle: The angle between the columella and the upper lip,while intersecting subnasale.

Otobasion inferior: The lowest point of attachment of the auricle to theskin of the face.

Otobasion superior: The highest point of attachment of the auricle tothe skin of the face.

Pronasale: the most protruded point or tip of the nose, which can beidentified in lateral view of the rest of the portion of the head.

Philtrum: the midline groove that runs from lower border of the nasalseptum to the top of the lip in the upper lip region.

Pogonion: Located on the soft tissue, the most anterior midpoint of thechin.

Ridge (nasal): The nasal ridge is the midline prominence of the nose,extending from the Sellion to the Pronasale.

Sagittal plane: A vertical plane that passes from anterior (front) toposterior (rear). The midsagittal plane is a sagittal plane that dividesthe body into right and left halves.

Sellion: Located on the soft tissue, the most concave point overlyingthe area of the frontonasal suture.

Septal cartilage (nasal): The nasal septal cartilage forms part of theseptum and divides the front part of the nasal cavity.

Subalare: The point at the lower margin of the alar base, where the alarbase joins with the skin of the superior (upper) lip.

Subnasal point: Located on the soft tissue, the point at which thecolumella merges with the upper lip in the midsagittal plane.

Supramenton: The point of greatest concavity in the midline of the lowerlip between labrale inferius and soft tissue pogonion

5.8.3.2 Anatomy of the Skull

Frontal bone: The frontal bone includes a large vertical portion, thesquama frontalis, corresponding to the region known as the forehead.

Mandible: The mandible forms the lower jaw. The mental protuberance isthe bony protuberance of the jaw that forms the chin.

Maxilla: The maxilla forms the upper jaw and is located above themandible and below the orbits. The frontal process of the maxillaprojects upwards by the side of the nose, and forms part of its lateralboundary.

Nasal bones: The nasal bones are two small oblong bones, varying in sizeand form in different individuals; they are placed side by side at themiddle and upper part of the face, and form, by their junction, the“bridge” of the nose.

Nasion: The intersection of the frontal bone and the two nasal bones, adepressed area directly between the eyes and superior to the bridge ofthe nose.

Occipital bone: The occipital bone is situated at the back and lowerpart of the cranium. It includes an oval aperture, the foramen magnum,through which the cranial cavity communicates with the vertebral canal.The curved plate behind the foramen magnum is the squama occipitalis.

Orbit: The bony cavity in the skull to contain the eyeball.

Parietal bones: The parietal bones are the bones that, when joinedtogether, form the roof and sides of the cranium.

Temporal bones: The temporal bones are situated on the bases and sidesof the skull, and support that part of the face known as the temple.

Zygomatic bones: The face includes two zygomatic bones, located in theupper and lateral parts of the face and forming the prominence of thecheek.

5.8.3.3 Anatomy of the Respiratory System

Diaphragm: A sheet of muscle that extends across the bottom of the ribcage. The diaphragm separates the thoracic cavity, containing the heart,lungs and ribs, from the abdominal cavity. As the diaphragm contractsthe volume of the thoracic cavity increases and air is drawn into thelungs.

Larynx: The larynx, or voice box houses the vocal folds and connects theinferior part of the pharynx (hypopharynx) with the trachea.

Lungs: The organs of respiration in humans. The conducting zone of thelungs contains the trachea, the bronchi, the bronchioles, and theterminal bronchioles. The respiratory zone contains the respiratorybronchioles, the alveolar ducts, and the alveoli.

Nasal cavity: The nasal cavity (or nasal fossa) is a large air filledspace above and behind the nose in the middle of the face. The nasalcavity is divided in two by a vertical fin called the nasal septum. Onthe sides of the nasal cavity are three horizontal outgrowths callednasal conchae (singular “concha”) or turbinates. To the front of thenasal cavity is the nose, while the back blends, via the choanae, intothe nasopharynx.

Pharynx: The part of the throat situated immediately inferior to (below)the nasal cavity, and superior to the oesophagus and larynx. The pharynxis conventionally divided into three sections: the nasopharynx(epipharynx) (the nasal part of the pharynx), the oropharynx(mesopharynx) (the oral part of the pharynx), and the laryngopharynx(hypopharynx).

5.8.4 Patient Interface

Anti-asphyxia valve (AAV): The component or sub-assembly of a masksystem that, by opening to atmosphere in a failsafe manner, reduces therisk of excessive CO₂ rebreathing by a patient.

Elbow: An elbow is an example of a structure that directs an axis offlow of air travelling therethrough to change direction through anangle. In one form, the angle may be approximately 90 degrees. Inanother form, the angle may be more, or less than 90 degrees. The elbowmay have an approximately circular cross-section. In another form theelbow may have an oval or a rectangular cross-section. In certain formsan elbow may be rotatable with respect to a mating component, e.g. about360 degrees. In certain forms an elbow may be removable from a matingcomponent, e.g. via a snap connection. In certain forms, an elbow may beassembled to a mating component via a one-time snap during manufacture,but not removable by a patient.

Frame: Frame will be taken to mean a mask structure that bears the loadof tension between two or more points of connection with a headgear. Amask frame may be a non-airtight load bearing structure in the mask.However, some forms of mask frame may also be air-tight.

Headgear. Headgear will be taken to mean a form of positioning andstabilising structure designed for use on a head. For example theheadgear may comprise a collection of one or more struts, ties andstiffeners configured to locate and retain a facial interface (e.g., apatient interface) in position on a patient's face for delivery ofrespiratory therapy. Some ties are formed of a soft, flexible, elasticmaterial such as a laminated composite of foam and fabric.

Membrane: Membrane will be taken to mean a typically thin element thathas, preferably, substantially no resistance to bending, but hasresistance to being stretched.

Plenum chamber: a mask plenum chamber will be taken to mean a portion ofa patient interface having walls at least partially enclosing a volumeof space, the volume having air therein pressurised above atmosphericpressure in use. A shell may form part of the walls of a mask plenumchamber.

Seal: May be a noun form (“a seal”) which refers to a structure, or averb form (“to seal”) which refers to the effect. Two elements may beconstructed and/or arranged to ‘seal’ or to effect ‘sealing’therebetween without requiring a separate ‘seal’ element per se.

Shell: A shell will be taken to mean a curved, relatively thin structurehaving bending, tensile and compressive stiffness. For example, a curvedstructural wall of a mask may be a shell. In some forms, a shell may befaceted. In some forms a shell may be airtight. In some forms a shellmay not be airtight.

Stiffener: A stiffener will be taken to mean a structural componentdesigned to increase the bending resistance of another component in atleast one direction.

Strut: A strut will be taken to be a structural component designed toincrease the compression resistance of another component in at least onedirection.

Swivel (noun): A subassembly of components configured to rotate about acommon axis, preferably independently, preferably under low torque. Inone form, the swivel may be constructed to rotate through an angle of atleast 360 degrees. In another form, the swivel may be constructed torotate through an angle less than 360 degrees. When used in the contextof an air delivery conduit, the sub-assembly of components preferablycomprises a matched pair of cylindrical conduits. There may be little orno leak flow of air from the swivel in use.

Tie (noun): A structure designed to resist tension.

Vent: (noun): A structure that allows a flow of air from an interior ofthe mask, or conduit, to ambient air for clinically effective washout ofexhaled gases. For example, a clinically effective washout may involve aflow rate of about 10 litres per minute to about 100 litres per minute,depending on the mask design and treatment pressure.

5.8.5 Shape of Structures

Products in accordance with the present technology may comprise one ormore three-dimensional mechanical structures, for example a mask cushionor an impeller. The three-dimensional structures may be bounded bytwo-dimensional surfaces. These surfaces may be distinguished using alabel to describe an associated surface orientation, location, function,or some other characteristic. For example a structure may comprise oneor more of an anterior surface, a posterior surface, an interior surfaceand an exterior surface. In another example, a seal-forming structuremay comprise a face-contacting (e.g. outer) surface, and a separatenon-face-contacting (e.g. underside or inner) surface. In anotherexample, a structure may comprise a first surface and a second surface.

To facilitate describing the shape of the three-dimensional structuresand the surfaces, we first consider a cross-section through a surface ofthe structure at a point, p. See FIG. 3B to FIG. 3F, which illustrateexamples of cross-sections at point p on a surface, and the resultingplane curves. FIGS. 3B to 3F also illustrate an outward normal vector atp. The outward normal vector at p points away from the surface. In someexamples we describe the surface from the point of view of an imaginarysmall person standing upright on the surface.

5.8.5.1 Curvature in One Dimension

The curvature of a plane curve at p may be described as having a sign(e.g. positive, negative) and a magnitude (e.g. 1/radius of a circlethat just touches the curve at p).

Positive curvature: If the curve at p turns towards the outward normal,the curvature at that point will be taken to be positive (if theimaginary small person leaves the point p they must walk uphill). SeeFIG. 3B (relatively large positive curvature compared to FIG. 3C) andFIG. 3C (relatively small positive curvature compared to FIG. 3B). Suchcurves are often referred to as concave.

Zero curvature: If the curve at p is a straight line, the curvature willbe taken to be zero (if the imaginary small person leaves the point p,they can walk on a level, neither up nor down). See FIG. 3D.

Negative curvature: If the curve at p turns away from the outwardnormal, the curvature in that direction at that point will be taken tobe negative (if the imaginary small person leaves the point p they mustwalk downhill). See FIG. 3E (relatively small negative curvaturecompared to FIG. 3F) and FIG. 3F (relatively large negative curvaturecompared to FIG. 3E). Such curves are often referred to as convex.

5.8.5.2 Curvature of Two Dimensional Surfaces

A description of the shape at a given point on a two-dimensional surfacein accordance with the present technology may include multiple normalcross-sections. The multiple cross-sections may cut the surface in aplane that includes the outward normal (a “normal plane”), and eachcross-section may be taken in a different direction. Each cross-sectionresults in a plane curve with a corresponding curvature. The differentcurvatures at that point may have the same sign, or a different sign.Each of the curvatures at that point has a magnitude, e.g. relativelysmall. The plane curves in FIGS. 3B to 3F could be examples of suchmultiple cross-sections at a particular point.

Principal curvatures and directions: The directions of the normal planeswhere the curvature of the curve takes its maximum and minimum valuesare called the principal directions. In the examples of FIG. 3B to FIG.3F, the maximum curvature occurs in FIG. 3B, and the minimum occurs inFIG. 3F, hence FIG. 3B and FIG. 3F are cross sections in the principaldirections. The principal curvatures at p are the curvatures in theprincipal directions.

Region of a surface: A connected set of points on a surface. The set ofpoints in a region may have similar characteristics, e.g. curvatures orsigns.

Saddle region: A region where at each point, the principal curvatureshave opposite signs, that is, one is positive, and the other is negative(depending on the direction to which the imaginary person turns, theymay walk uphill or downhill).

Dome region: A region where at each point the principal curvatures havethe same sign, e.g. both positive (a “concave dome”) or both negative (a“convex dome”).

Cylindrical region: A region where one principal curvature is zero (or,for example, zero within manufacturing tolerances) and the otherprincipal curvature is non-zero.

Planar region: A region of a surface where both of the principalcurvatures are zero (or, for example, zero within manufacturingtolerances).

Edge of a surface: A boundary or limit of a surface or region.

Path: In certain forms of the present technology, ‘path’ will be takento mean a path in the mathematical—topological sense, e.g. a continuousspace curve from f(0) to f(1) on a surface. In certain forms of thepresent technology, a ‘path’ may be described as a route or course,including e.g. a set of points on a surface. (The path for the imaginaryperson is where they walk on the surface, and is analogous to a gardenpath).

Path length: In certain forms of the present technology, ‘path length’will be taken to mean the distance along the surface from f(0) to f(1),that is, the distance along the path on the surface. There may be morethan one path between two points on a surface and such paths may havedifferent path lengths. (The path length for the imaginary person wouldbe the distance they have to walk on the surface along the path).

Straight-line distance: The straight-line distance is the distancebetween two points on a surface, but without regard to the surface. Onplanar regions, there would be a path on the surface having the samepath length as the straight-line distance between two points on thesurface. On non-planar surfaces, there may be no paths having the samepath length as the straight-line distance between two points. (For theimaginary person, the straight-line distance would correspond to thedistance ‘as the crow flies’.)

5.8.5.3 Space Curves

Space curves: Unlike a plane curve, a space curve does not necessarilylie in any particular plane. A space curve may be closed, that is,having no endpoints. A space curve may be considered to be aone-dimensional piece of three-dimensional space. An imaginary personwalking on a strand of the DNA helix walks along a space curve. Atypical human left ear comprises a helix, which is a left-hand helix,see FIG. 3Q. A typical human right ear comprises a helix, which is aright-hand helix, see FIG. 3R. FIG. 3S shows a right-hand helix. Theedge of a structure, e.g. the edge of a membrane or impeller, may followa space curve. In general, a space curve may be described by a curvatureand a torsion at each point on the space curve. Torsion is a measure ofhow the curve turns out of a plane. Torsion has a sign and a magnitude.The torsion at a point on a space curve may be characterised withreference to the tangent, normal and binormal vectors at that point.

Tangent unit vector (or unit tangent vector): For each point on a curve,a vector at the point specifies a direction from that point, as well asa magnitude. A tangent unit vector is a unit vector pointing in the samedirection as the curve at that point. If an imaginary person were flyingalong the curve and fell off her vehicle at a particular point, thedirection of the tangent vector is the direction she would betravelling.

Unit normal vector: As the imaginary person moves along the curve, thistangent vector itself changes. The unit vector pointing in the samedirection that the tangent vector is changing is called the unitprincipal normal vector. It is perpendicular to the tangent vector.

Binormal unit vector: The binormal unit vector is perpendicular to boththe tangent vector and the principal normal vector. Its direction may bedetermined by a right-hand rule (see e.g. FIG. 3P), or alternatively bya left-hand rule (FIG. 3O).

Osculating plane: The plane containing the unit tangent vector and theunit principal normal vector. See FIGS. 3O and 3P.

Torsion of a space curve: The torsion at a point of a space curve is themagnitude of the rate of change of the binormal unit vector at thatpoint. It measures how much the curve deviates from the osculatingplane. A space curve which lies in a plane has zero torsion. A spacecurve which deviates a relatively small amount from the osculating planewill have a relatively small magnitude of torsion (e.g. a gently slopinghelical path). A space curve which deviates a relatively large amountfrom the osculating plane will have a relatively large magnitude oftorsion (e.g. a steeply sloping helical path). With reference to FIG.3S, since T2>T1, the magnitude of the torsion near the top coils of thehelix of FIG. 3S is greater than the magnitude of the torsion of thebottom coils of the helix of FIG. 3S

With reference to the right-hand rule of FIG. 3P, a space curve turningtowards the direction of the right-hand binormal may be considered ashaving a right-hand positive torsion (e.g. a right-hand helix as shownin FIG. 3S). A space curve turning away from the direction of theright-hand binormal may be considered as having a right-hand negativetorsion (e.g. a left-hand helix).

Equivalently, and with reference to a left-hand rule (see FIG. 3O), aspace curve turning towards the direction of the left-hand binormal maybe considered as having a left-hand positive torsion (e.g. a left-handhelix). Hence left-hand positive is equivalent to right-hand negative.See FIG. 3T.

5.8.5.4 Holes

A surface may have a one-dimensional hole, e.g. a hole bounded by aplane curve or by a space curve. Thin structures (e.g. a membrane) witha hole, may be described as having a one-dimensional hole. See forexample the one dimensional hole in the surface of structure shown inFIG. 3I, bounded by a plane curve.

A structure may have a two-dimensional hole, e.g. a hole bounded by asurface. For example, an inflatable tyre has a two dimensional holebounded by the interior surface of the tyre. In another example, abladder with a cavity for air or gel could have a two-dimensional hole.See for example the cushion of FIG. 3L and the example cross-sectionstherethrough in FIG. 3M and FIG. 3N, with the interior surface boundinga two dimensional hole indicated. In a yet another example, a conduitmay comprise a one-dimension hole (e.g. at its entrance or at its exit),and a two-dimension hole bounded by the inside surface of the conduit.See also the two dimensional hole through the structure shown in FIG.3K, bounded by a surface as shown.

5.9 Other Remarks

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in Patent Office patent files orrecords, but otherwise reserves all copyright rights whatsoever.

Unless the context clearly dictates otherwise and where a range ofvalues is provided, it is understood that each intervening value, to thetenth of the unit of the lower limit, between the upper and lower limitof that range, and any other stated or intervening value in that statedrange is encompassed within the technology. The upper and lower limitsof these intervening ranges, which may be independently included in theintervening ranges, are also encompassed within the technology, subjectto any specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the technology.

Furthermore, where a value or values are stated herein as beingimplemented as part of the technology, it is understood that such valuesmay be approximated, unless otherwise stated, and such values may beutilized to any suitable significant digit to the extent that apractical technical implementation may permit or require it.

Furthermore, “approximately”, “substantially”, “about”, or any similarterm as used herein means +/−5 to +/−10% of the recited value.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this technology belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present technology, a limitednumber of the exemplary methods and materials are described herein.

When a particular material is identified as being used to construct acomponent, obvious alternative materials with similar properties may beused as a substitute. Furthermore, unless specified to the contrary, anyand all components herein described are understood to be capable ofbeing manufactured and, as such, may be manufactured together orseparately.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include their plural equivalents,unless the context clearly dictates otherwise.

All publications mentioned herein are incorporated herein by referencein their entirety to disclose and describe the methods and/or materialswhich are the subject of those publications. The publications discussedherein are provided solely for their disclosure prior to the filing dateof the present application. Nothing herein is to be construed as anadmission that the present technology is not entitled to antedate suchpublication by virtue of prior invention. Further, the dates ofpublication provided may be different from the actual publication dates,which may need to be independently confirmed.

The terms “comprises” and “comprising” should be interpreted asreferring to elements, components, or steps in a non-exclusive manner,indicating that the referenced elements, components, or steps may bepresent, or utilized, or combined with other elements, components, orsteps that are not expressly referenced.

The subject headings used in the detailed description are included onlyfor the ease of reference of the reader and should not be used to limitthe subject matter found throughout the disclosure or the claims. Thesubject headings should not be used in construing the scope of theclaims or the claim limitations.

Although the technology herein has been described with reference toparticular examples, it is to be understood that these examples aremerely illustrative of the principles and applications of thetechnology. In some instances, the terminology and symbols may implyspecific details that are not required to practice the technology. Forexample, although the terms “first” and “second” may be used, unlessotherwise specified, they are not intended to indicate any order but maybe utilised to distinguish between distinct elements. Furthermore,although process steps in the methodologies may be described orillustrated in an order, such an ordering is not required. Those skilledin the art will recognize that such ordering may be modified and/oraspects thereof may be conducted concurrently or even synchronously.

It is therefore to be understood that numerous modifications may be madeto the illustrative examples and that other arrangements may be devisedwithout departing from the spirit and scope of the technology.

5.10 REFERENCE SIGNS LIST patient 1000 bed partner 1100 patientinterface 3000 seal - forming structure 3100 plenum chamber 3200 orifice3202 chord 3210 projection 3212 superior point 3220 inferior point 3230structure 3300 headgear assembly 3302 sleeve 3304 first portion 3304asecond portion 3304b single rigidized arm 3306 rigidized arm 3306 cavity3308 first rear section 3310a second rear section 3310b fastener 3312opening 3315 plug 3316 body 3320 first body portion 3320a second bodyportion 3320b aperture 3324 arm portion 3328 end 3329 free end 3330inner coupling 3334 outer coupling 3338 free end 3342 projections 3346axis 3348 cover 3354 fluid conduit 3358 inlet 3362 rear strap 3366 tabs3370 vent 3400 connection port 3600 forehead support 3700 ISO 3744 RPTdevice 4000 external housing 4010 upper portion 4012 portion 4014 panel4015 chassis 4016 handle 4018 pneumatic block 4020 air filter 4110 inletair filter 4112 outlet air filter 4114 muffler 4120 inlet muffler 4122outlet muffler 4124 pressure generator 4140 blower 4142 motor 4144anti - spill back valve 4160 air circuit 4170 ring 4171 supplementarygas 4180 electrical components 4200 single Printed Circuit 4202 BoardAssembly PCBA power supply 4210 input device 4220 transducer 4270humidifier 5000

What is claimed is:
 1. A patient interface comprising: a plenum chamberpressurisable to a therapeutic pressure of at least 6 cmH2O aboveambient air pressure, said plenum chamber including a plenum chamberinlet port sized and structured to receive a flow of air at thetherapeutic pressure for breathing by a patient; a seal-formingstructure constructed and arranged to form a seal with a region of thepatient's face surrounding an entrance to the patient's airways, saidseal forming structure having a hole therein such that the flow of airat said therapeutic pressure is delivered to at least an entrance to thepatient's nares, the seal-forming structure constructed and arranged tomaintain said therapeutic pressure in the plenum chamber throughout thepatient's respiratory cycle in use; and a positioning and stabilisingstructure to provide a force to hold a seal forming structure in atherapeutically effective position on the patient's head, thepositioning and stabilising structure comprising: at least one rigidizedarm configured, in use, to be positioned adjacent to a cheek of thepatient; and a strap removably received around the rigidized arm andconfigured to contact, in use, a posterior region of the patient's head,the strap comprising, a first rigid coupling forming an opening to acavity, the rigidized arm being positionable through the opening andinto the cavity, the first rigid coupling having a mechanical connectorthat is configured to engage the rigidized arm and limit movement of therigidized arm into and out of the cavity, a second rigid coupling spacedapart from an outer surface of the first rigid coupling, and a sleeveconstructed from a flexible material, the sleeve being folded over thesecond rigid coupling and positioned between the first rigid couplingand the second rigid coupling.
 2. The patient interface of claim 1,wherein the sleeve includes an outer surface that comprises an outermostsurface of the strap, and an inner surface that comprises a boundary ofthe cavity.
 3. The patient interface of claim 1, wherein the mechanicalconnector of the first rigid coupling includes a projection, and therigidized arm includes a recess configured to receive the projection. 4.The patient interface of claim 3, wherein the projection extends at anangle between 40° and 60° from an inner surface of the first rigidcoupling, the angle measured with respect to an axis that is parallel toa radial axis of the first rigid coupling.
 5. The patient interface ofclaim 1, wherein the mechanical connector comprises a snap-fitconnection.
 6. The patient interface of claim 1, wherein the flexiblematerial is a textile.
 7. The patient interface of claim 1, wherein theflexible material is elastic and/or elastomeric.
 8. The patientinterface of claim 1, wherein the first rigid coupling and the secondrigid coupling have a generally circular shape, the rigidized armfurther including an extension having at least a portion of thegenerally circular shape.
 9. The patient interface of claim 1, whereinthe rigidized arm is configured to not extend in a posterior directionfurther than the patient's ear.
 10. The patient interface of claim 1,wherein the strap includes a first piece and a second piece coupledtogether using a length adjuster, wherein the length adjuster isconfigured to change a usable length of the strap.
 11. The patientinterface of claim 1, wherein the strap is bifurcated.
 12. The patientinterface of claim 1, wherein; the at least one rigidized arm comprisesa first rigidized arm configured, in use, to be positioned on a leftside of the patient's head, a second rigidized arm coupled to thepositioning and stabilising structure and configured, in use, to bepositioned adjacent to a right cheek of the patient, and the strap isremovably received around the second rigidized arm, the strapcomprising: a third rigid coupling defining a second opening to thecavity, the second rigidized arm being positionable through the secondopening and into the cavity, the third rigid coupling having amechanical connector that engages the second rigidized arm and limitsmovement of the second rigidized arm into and out of the second openingof the cavity, a fourth rigid coupling spaced apart from an outersurface of the first rigid coupling, and the sleeve being folded overthe fourth rigid coupling and positioned between the third rigidcoupling and the fourth rigid coupling.
 13. The patient interface ofclaim 1, wherein the plenum chamber inlet port is a first plenum chamberinlet port, the plenum chamber further includes a second plenum chamberinlet port, the first plenum chamber inlet port configured to receivethe flow of air at the therapeutic pressure, and the second plenumchamber inlet port configured to receive a plug configured to preventthe flow of air at the therapeutic pressure from escaping.
 14. Thepatient interface of claim 13, wherein the rigidized arm includes theplug.
 15. The patient interface of claim 13, wherein the plug isremovable from the second opening in order to permit pressurized air toflow through the second opening.
 16. The patient interface of claim 1,wherein the rigidized arm is at least partially flexible in order toadjust a contour to substantially correspond to the cheek of thepatient.
 17. The patient interface of claim 1, wherein the seal formingstructure defines nasal pillows or a cradle.
 18. The patient interfaceof claim 1, wherein the first rigid coupling, the second rigid coupling,and the sleeve are coupled together using an adhesive.
 19. The patientinterface of claim 1, wherein the cavity includes a width less than awidth of the rigidized arm, and wherein the sleeve is configured tostretch upon receiving the rigidized arm.
 20. A method of manufacturingthe patient interface of claim 1, the method comprising forming thestrap by: providing the flexible material; inserting the second couplinginto the cavity of the flexible material; folding an end of the flexiblematerial into the cavity to enclose the second coupling; and insertingthe first coupling into the cavity.
 21. The method of claim 20, themethod further comprising the steps of connecting the positioning andstabilising structure to the seal-forming structure by: providing aplenum chamber with a connection opening; and inserting a plug of therigidized arm into the connection opening.
 22. The method of claim 21,the method further comprising applying an adhesive around the connectionopening in order to secure the plug within the opening.
 23. The methodof claim 21, the method further comprising removing the plug from theconnection opening.